refactor: update SmartPointer default constructor to initialize as null and add comprehensive documentation

.agents/rules/micromamba_build.md

@@ -1,6 +1,10 @@
-# Skill: Build uLib with Micromamba
+---
+trigger: always_on
+---
 
-This skill provides instructions for building the uLib project using the micromamba environment.
+# Rule: Build uLib with Micromamba
+
+This rule provides instructions for building the uLib project using the micromamba environment.
 
 ## Context
 - **Environment**: micromamba `uLib`
@@ -14,26 +18,27 @@ This skill provides instructions for building the uLib project using the microma
    ```bash
    export MAMBA_EXE="/home/share/micromamba/bin/micromamba"
    export MAMBA_ROOT_PREFIX="/home/share/micromamba"
-   eval "$(/home/share/micromamba/bin/micromamba shell hook --shell bash)"
+   export PRESET="clang-debug"
+   eval "$(${MAMBA_EXE} shell hook --shell bash)"
    micromamba activate uLib
    ```
 
 2. **Full Rebuild (if needed)**:
    If the `build` directory does not exist or a full reconfiguration is required:
    ```bash
-   conan profile detect --force
+   conan install . --output-folder=build/${PRESET} --build=missing --profile=fast
-   conan install . --output-folder=build --build=missing
+   cmake --preset ${PRESET}
-   cmake --preset conan-release
+   cmake --build build/${PRESET} -j$(nproc)
    ```
 
 3. **Incremental Build**:
    Run the build command from the root directory, pointing to the `build` folder and using all cores.
    ```bash
-   cmake --build build -j$(nproc)
+   cmake --build build/${PRESET} -j$(nproc)
    ```
 
-4. **Specific Target Build**:
+4. **Specific Target Build - gcompose**:
    To build a specific target (e.g., gcompose):
    ```bash
-   cmake --build build --target gcompose -j$(nproc)
+   cmake --build build/${PRESET} --target gcompose -j$(nproc)
    ```

.agents/skills/core_system.md

@@ -0,0 +1,49 @@
+# Skill: Core Object & Property System
+
+This skill defines the patterns for implementing and working with the `uLib` core object model.
+
+## Context
+- **Base Class**: `uLib::Object`
+- **Property System**: `uLib::Property<T>`
+- **Registration**: All objects must register their properties for UI visibility and serialization.
+
+## Implementation Patterns
+
+### 1. Defining an Object
+Inherit from `uLib::Object` and use the `ULIB_PROPERTY` macro for members.
+```cpp
+class MyObject : public uLib::Object {
+public:
+    ULIB_PROPERTY(double, Speed, 0.0)
+    ULIB_PROPERTY(std::string, Description, "None")
+    
+    MyObject() {
+        // Required for property visibility in PropertyEditor
+        ULIB_ACTIVATE_PROPERTIES(*this)
+    }
+};
+```
+
+### 2. Property Access
+Properties can be treated like their underlying types or accessed via `.Get()`/`.Set()`.
+```cpp
+obj.Speed = 10.5;                // Triggers Updated() signal
+double s = obj.Speed;            // Implicit conversion
+obj.Speed.SetRange(0.0, 100.0);  // Setting metadata
+```
+
+### 3. Serialization
+Implement `serialize` overloads for different archive types. Use `hrp` (Human Readable Property) to name fields.
+```cpp
+template <class ArchiveT>
+void serialize(ArchiveT &ar, const unsigned int version) {
+    ar & boost::serialization::make_nvp("InstanceName", this->GetInstanceName());
+    ar & boost::serialization::make_hrp("Speed", Speed, "m/s");
+}
+```
+
+## Checklist
+- [ ] Inherit from `uLib::Object`.
+- [ ] Use `ULIB_PROPERTY` for members that should appear in the GUI.
+- [ ] Call `ULIB_ACTIVATE_PROPERTIES` in the constructor.
+- [ ] Implement `serialize` if persistence is required.

.agents/skills/geant_simulation.md

@@ -0,0 +1,39 @@
+# Skill: HEP/Geant Simulation Rules
+
+This skill provides instructions for developing the Geant4 simulation components within `uLib`.
+
+## Context
+- **Domain Objects**: `Material`, `Solid`, `LogicalVolume`, `PhysicalVolume`.
+- **Integration**: `mutomGeant` library wraps Geant4 classes into `uLib::Object`s.
+
+## Patterns
+
+### 1. Adding a New Solid
+New solids must implement `GetPolyhedron()` to support VTK visualization.
+```cpp
+G4Polyhedron* MySolid::GetPolyhedron() const {
+    // Return the tessellated representation of the Geant4 solid
+    return m_G4Solid->GetPolyhedron();
+}
+```
+
+### 2. Physical Volume Hierarchy
+Maintain the relationship between `PhysicalVolume` and its parent `LogicalVolume`.
+```cpp
+auto* world = new LogicalVolume(worldSolid, worldMat);
+auto* detector = new PhysicalVolume(detectorLogic, world, "Detector1");
+detector->SetPosition({0, 0, 100}); // Relative to parent
+```
+
+### 3. Transformation Synchronization
+Use the centralized `TRS` object to manage position and rotation. Synchronization with Geant4's internal stores should be reactive.
+- Listen to `Object::Updated` on the `Solid` or `PhysicalVolume`.
+- Update the underlying `G4VPhysicalVolume` position/rotation.
+
+## Material Management
+Use the `Matter` class to manage Geant4 materials. Ensure materials are registered in the `G4NistManager` or custom material store if needed.
+
+## Checklist
+- [ ] Does the solid implement `GetPolyhedron()`?
+- [ ] Are parents correctly assigned in `PhysicalVolume` constructors?
+- [ ] Is the `TRS` object used for all spatial transformations?

.agents/skills/memory_management.md

@@ -0,0 +1,40 @@
+# Skill: Memory Management & Object Lifecycle
+
+This skill provides guidelines for managing memory safely within the `uLib` framework to prevent memory corruption and leaks.
+
+## Context
+- **Ownership**: `ObjectsContext` typically owns its children.
+- **Shared Access**: Use `SmartPointer<T>` for objects shared across multiple systems (e.g., Geant4 and VTK).
+- **Core Principle**: Avoid manual `delete` on objects managed by the framework.
+
+## Patterns
+
+### 1. Context Ownership
+When an object is added to an `ObjectsContext`, it is managed by that context.
+```cpp
+auto* context = new ObjectsContext();
+auto* obj = new MyObject();
+context->AddObject(obj); 
+// Do NOT delete obj; it will be deleted when context is destroyed.
+```
+
+### 2. Smart Pointers
+Use `SmartPointer<T>` for resources like `Material` or `Solid` that are used by both domain logic and external engines (Geant4).
+```cpp
+uLib::SmartPointer<Material> mat = new Material("Lead");
+solid->SetMaterial(mat); // Shared ownership
+```
+
+### 3. Geant4 Object Safety
+Geant4 often takes ownership of certain objects (like `G4VPhysicalVolume`). When wrapping these:
+- Ensure the wrapper doesn't double-free the Geant4-owned pointer.
+- Use `recursion_guard` if synchronizing transformations between `uLib::Object` and Geant4 volumes to prevent signal loops.
+
+## Debugging Memory Issues
+- **SIGABRT (invalid pointer)**: Usually caused by deleting an object that was already managed (and deleted) by an `ObjectsContext` or `SmartPointer`.
+- **Leaks**: Check if objects were created but never added to a context or wrapped in a `SmartPointer`.
+
+## Checklist
+- [ ] Are objects added to an `ObjectsContext`?
+- [ ] Is `SmartPointer` used for shared resources?
+- [ ] Is there a risk of double-freeing Geant4-managed pointers?

.agents/skills/object_context.md

@@ -0,0 +1,29 @@
+# Skill: Object Context & Scene Management
+
+Guidelines for managing the `uLib` object hierarchy, Geant4 volume instantiation, and Gcompose scene interaction.
+
+## 1. Object Creation & Context
+- **Factory Pattern**: Always use `ObjectFactory` to instantiate objects from the registry. Avoid direct `new` calls for domain objects to ensure proper metadata and property initialization.
+- **Context Ownership**: The `Context` is the source of truth. Every persistent object must be registered within the `Context` to participate in the tree hierarchy, property system, and serialization.
+
+## 2. Geant4: Logical vs. Physical Volumes
+In the Geant4/HEP domain, visibility and placement follow a strict two-tier hierarchy:
+- **LogicalVolume**: Defines **what** the object is (Solid/Shape, Material, and daughter volumes). It is a template and does **not** have a spatial position.
+- **PhysicalVolume**: Defines **where** and **how** an instance exists. It references a `LogicalVolume` and holds the **TRS** (Translation, Rotation Matrix/Scale).
+- **CRITICAL**: Adding a `Solid` or `LogicalVolume` to the scene is insufficient for visualization. To display an object in the VTK viewport, you **must**:
+    1. Define the `LogicalVolume`.
+    2. Instantiate a `PhysicalVolume` from that `LogicalVolume`.
+    3. Add the `PhysicalVolume` to the scene context and apply TRS transformations to it.
+
+## 3. Gcompose: Tree Hierarchy & Visualization
+- **3D Representations**: Objects with 3D actors are automatically wrapped in VTK representations (e.g., `vtkContainerBox`). Non-3D objects remain in the tree but have no viewport presence.
+- **Reference Handling**: 
+    - Internal object references (raw pointers or `SmartPointer`) are rendered as "virtual children" in the tree.
+    - **Instance Re-use**: One object can appear as a child under multiple parents if referenced multiple times; these are placeholders for the same underlying instance.
+- **Setting References**:
+    - **Property Selector**: Filter and select compatible types from the global context within the property editor.
+    - **Drag & Drop**: Drag an object from the tree and drop it onto a property field. The system automatically validates types and performs the necessary casting/assignment.
+
+## 4. Best Practices & Checks
+- **TRS Logic**: Always apply transformations to the `PhysicalVolume`. Changes to a `LogicalVolume` will affect all its instances but will not move them.
+- **Dependency Tracking**: Use the tree structure to identify shared references. Changing a property on a shared object affects all parent nodes that reference it.

.agents/skills/signal_bridge.md

@@ -0,0 +1,34 @@
+# Skill: Multi-System Signaling (uLib ↔ Qt)
+
+This skill manages the coexistence of `uLib::Object` signals and Qt's `Q_OBJECT` signaling system.
+
+## Context
+- **uLib Signals**: Used for domain logic and data changes (`uLib::Object::connect`).
+- **Qt Signals**: Used for UI events, widgets, and application-level control flow (`QObject::connect`).
+
+## Patterns
+
+### 1. Bridging Logic
+When a domain change needs to trigger a UI update, use a wrapper or a direct connection if the widget has access to the `uLib::Object`.
+```cpp
+// In a Qt Widget
+uLib::Object::connect(domainObj, &Object::Updated, [this]() {
+    this->update(); // Trigger Qt repaint
+});
+```
+
+### 2. Selection Flow
+Selection usually starts in the VTK Viewport (Qt) and flows to the domain context.
+1. `QViewport` emits `prop3dSelected(Prop3D*)` (Qt signal).
+2. `MainPanel` catches it and calls `contextPanel->selectObject(p->GetContent())`.
+3. `ContextPanel` updates the tree view and property editors.
+
+### 3. Connection Hygiene
+- Use `uLib::Object::connect` for everything involving `uLib::Property` changes.
+- Use Qt `connect` for button clicks, menu actions, and window events.
+- Be careful with lambda captures; ensure the captured object is still alive or use weak pointers if necessary.
+
+## Checklist
+- [ ] Is the correct signaling system being used for the task?
+- [ ] Are capture groups in lambdas safe?
+- [ ] Does selection flow correctly between the 3D view and the tree view?

.agents/skills/testing_guide.md

@@ -0,0 +1,34 @@
+# Skill: Standardized Testing & Validation
+
+This skill provides the standard workflow for testing and validating changes in the `uLib` project.
+
+## Context
+- **Tooling**: `ctest` and direct execution of test binaries in the `build/` directory.
+- **Location**: Test binaries are typically located in `build/src/*/testing/` or `build/Testing/`.
+
+## Workflow
+
+### 1. Running All Tests
+From the root directory:
+```bash
+ctest --test-dir build/clang-make --output-on-failure
+```
+
+### 2. Running Component Tests
+Run specific categories of tests:
+- **Core**: `./build/clang-make/src/Core/testing/CoreTest`
+- **Math**: `./build/clang-make/src/Math/testing/MathVectorTest`
+- **Geant**: `./build/clang-make/src/HEP/Geant/testing/GeantApp`
+- **VTK**: `./build/clang-make/src/Vtk/testing/vtkViewerTest`
+
+### 3. Debugging a Failing Test
+Run the binary directly through `gdb` or `valgrind` (if available):
+```bash
+gdb --args ./build/clang-make/src/Core/testing/ObjectWrapperTest
+```
+
+## Validation Checklist for New Features
+- [ ] Does `ctest` pass globally?
+- [ ] If changing visualization, does `vtkViewerTest` show the correct results?
+- [ ] If changing Geant logic, does `GeantApp` run without memory aborts?
+- [ ] Are new tests added to the appropriate `CMakeLists.txt`?

.agents/skills/vtk_visualization.md

@@ -0,0 +1,52 @@
+# Skill: VTK Visualization Pipeline
+
+This skill defines how to bridge domain objects with the VTK 3D visualization layer.
+
+## Context
+- **Wrapper**: `Prop3D` (wraps a `vtkProp`).
+- **Mapping**: `Viewport` maintains `m_ObjectToProp3D` for synchronization.
+- **GUI Integration**: `QViewport` handles Qt events and selection signals.
+
+## Implementation Patterns
+
+### 1. Creating a Prop3D
+A `Prop3D` should wrap a domain object and update its visual state when the object changes.
+```cpp
+class MyProp3D : public Prop3D {
+public:
+    MyProp3D(MyObject* obj) : Prop3D(obj) {
+        // Connect domain updates to visual refreshes
+        uLib::Object::connect(obj, &Object::Updated, [this]() { this->SyncFromObject(); });
+        
+        // Expose properties to the VTK side-panel
+        ULIB_ACTIVATE_DISPLAY_PROPERTIES(*this)
+    }
+    
+    void SyncFromObject() {
+        // Update VTK actors/mappers from MyObject's properties
+    }
+};
+```
+
+### 2. Display Properties
+Use `serialize_display` to choose which properties of the domain object or the `Prop3D` itself are visible in the sliding "Display Properties" panel in `gcompose`.
+```cpp
+void serialize_display(Archive::display_properties_archive &ar) {
+    ar & boost::serialization::make_hrp("Opacity", m_Opacity);
+    ar & boost::serialization::make_hrp("Wireframe", m_Wireframe);
+}
+```
+
+### 3. Transformation Sync (TRS)
+Always synchronize the object's `trs` (Translate, Rotate, Scale) with the VTK actor's user transform.
+```cpp
+void UpdateTransform() {
+    auto matrix = GetContent()->GetTransform().GetMatrix();
+    m_Actor->SetUserMatrix(uLib::ToVtkMatrix(matrix));
+}
+```
+
+## Checklist
+- [ ] Does the `Prop3D` connect to the object's `Updated()` signal?
+- [ ] Are `ULIB_ACTIVATE_DISPLAY_PROPERTIES` and `serialize_display` implemented?
+- [ ] Is the transformation (TRS) correctly mapped to the VTK actor?

.vscode/settings.json

@@ -1,13 +1,14 @@
 {
+    "clangd.path": "/home/share/micromamba/envs/uLib/bin/clangd",
     "clangd.fallbackFlags": [
         "-I/home/rigoni/devel/cmt/uLib/src",
-        "-isystem/home/share/micromamba/envs/mutom/include",
+        "-isystem/home/share/micromamba/envs/uLib/include",
-        "-isystem/home/share/micromamba/envs/mutom/include/eigen3",
+        "-isystem/home/share/micromamba/envs/uLib/include/eigen3",
-        "-isystem/home/share/micromamba/envs/mutom/targets/x86_64-linux/include",
+        "-isystem/home/share/micromamba/envs/uLib/targets/x86_64-linux/include",
-        "-isystem/home/share/micromamba/envs/mutom/lib/gcc/x86_64-conda-linux-gnu/14.3.0/include/c++",
+        "-isystem/home/share/micromamba/envs/uLib/lib/gcc/x86_64-conda-linux-gnu/14.3.0/include/c++",
-        "-isystem/home/share/micromamba/envs/mutom/lib/gcc/x86_64-conda-linux-gnu/14.3.0/include/c++/x86_64-conda-linux-gnu",
+        "-isystem/home/share/micromamba/envs/uLib/lib/gcc/x86_64-conda-linux-gnu/14.3.0/include/c++/x86_64-conda-linux-gnu",
-        "-isystem/home/share/micromamba/envs/mutom/x86_64-conda-linux-gnu/sysroot/usr/include",
+        "-isystem/home/share/micromamba/envs/uLib/x86_64-conda-linux-gnu/sysroot/usr/include",
-        "--gcc-toolchain=/home/share/micromamba/envs/mutom",
+        "--gcc-toolchain=/home/share/micromamba/envs/uLib",
         "-D__host__=",
         "-D__device__=",
         "-D__global__=",
@@ -18,8 +19,8 @@
     ],
     "clangd.semanticHighlighting.enable": true,
     "clangd.arguments": [
-        "--compile-commands-dir=build",
+        "--compile-commands-dir=build/clang-make",
-        "--query-driver=/home/share/micromamba/envs/mutom/bin/*",
+        "--query-driver=/home/share/micromamba/envs/uLib/bin/*",
         "--all-scopes-completion",
         "--completion-style=detailed",
         "--header-insertion=never",
@@ -27,5 +28,6 @@
         "--pch-storage=memory",
         "--background-index",
         "--log=verbose"
-    ]
+    ],
+    "C_Cpp.intelliSenseEngine": "disabled"
 }

CMakeLists.txt

@@ -3,10 +3,31 @@
 ##### CMAKE LISTS ##############################################################
 ################################################################################
 
+# Save compiler and launcher paths if they are absolute (e.g. from presets or CLI)
+# to prevent conan_toolchain.cmake from overwriting them with relative names.
+set(_ULIB_SAVE_CC  "${CMAKE_C_COMPILER}")
+set(_ULIB_SAVE_CXX "${CMAKE_CXX_COMPILER}")
+set(_ULIB_SAVE_CC_LAUNCHER  "${CMAKE_C_COMPILER_LAUNCHER}")
+set(_ULIB_SAVE_CXX_LAUNCHER "${CMAKE_CXX_COMPILER_LAUNCHER}")
+
 if(EXISTS "${CMAKE_BINARY_DIR}/conan_toolchain.cmake")
     include("${CMAKE_BINARY_DIR}/conan_toolchain.cmake")
 endif()
 
+if(_ULIB_SAVE_CC AND IS_ABSOLUTE "${_ULIB_SAVE_CC}")
+    set(CMAKE_C_COMPILER "${_ULIB_SAVE_CC}" CACHE FILEPATH "C compiler" FORCE)
+endif()
+if(_ULIB_SAVE_CXX AND IS_ABSOLUTE "${_ULIB_SAVE_CXX}")
+    set(CMAKE_CXX_COMPILER "${_ULIB_SAVE_CXX}" CACHE FILEPATH "C++ compiler" FORCE)
+endif()
+if(_ULIB_SAVE_CC_LAUNCHER AND IS_ABSOLUTE "${_ULIB_SAVE_CC_LAUNCHER}")
+    set(CMAKE_C_COMPILER_LAUNCHER "${_ULIB_SAVE_CC_LAUNCHER}" CACHE FILEPATH "C compiler launcher" FORCE)
+endif()
+if(_ULIB_SAVE_CXX_LAUNCHER AND IS_ABSOLUTE "${_ULIB_SAVE_CXX_LAUNCHER}")
+    set(CMAKE_CXX_COMPILER_LAUNCHER "${_ULIB_SAVE_CXX_LAUNCHER}" CACHE FILEPATH "C++ compiler launcher" FORCE)
+endif()
+
+
 cmake_minimum_required (VERSION 3.26)
 
 set(QT_NO_VERSION_CHECK TRUE)

CMakePresets.json

@@ -2,37 +2,64 @@
     "version": 8,
     "configurePresets": [
         {
-            "name": "andrea",
+            "name": "gcc-make",
             "displayName": "Custom configure preset",
-            "description": "Sets Ninja generator, build and install directory",
+            "description": "Sets Makefile generator, build and install directory",
-            "generator": "Ninja",
+            "generator": "Unix Makefiles",
-            "binaryDir": "${sourceDir}/out/build/${presetName}",
+            "binaryDir": "${sourceDir}/build/${presetName}",
             "cacheVariables": {
                 "CMAKE_BUILD_TYPE": "Debug",
                 "CMAKE_INSTALL_PREFIX": "${sourceDir}/out/install/${presetName}"
             }
         },
         {
-            "name": "fast",
+            "name": "clang-ninja",
-            "displayName": "Fast build: Ninja + clang + ccache",
+            "displayName": "Ninja + clang + ccache",
             "description": "Uses Ninja generator, clang/lld compiler, and ccache",
             "generator": "Ninja",
-            "binaryDir": "${sourceDir}/build",
+            "binaryDir": "${sourceDir}/build/${presetName}",
             "cacheVariables": {
                 "CMAKE_BUILD_TYPE": "Release",
-                "CMAKE_C_COMPILER": "clang",
+                "CMAKE_C_COMPILER": "/home/share/micromamba/envs/uLib/bin/clang",
-                "CMAKE_CXX_COMPILER": "clang++",
+                "CMAKE_CXX_COMPILER": "/home/share/micromamba/envs/uLib/bin/clang++",
                 "CMAKE_EXE_LINKER_FLAGS": "-fuse-ld=lld",
                 "CMAKE_SHARED_LINKER_FLAGS": "-fuse-ld=lld",
-                "CMAKE_CXX_COMPILER_LAUNCHER": "ccache",
+                "CMAKE_CXX_COMPILER_LAUNCHER": "/home/share/micromamba/envs/uLib/bin/ccache",
-                "CMAKE_C_COMPILER_LAUNCHER": "ccache"
+                "CMAKE_C_COMPILER_LAUNCHER": "/home/share/micromamba/envs/uLib/bin/ccache"
             }
         },
         {
-            "name": "mutom",
+            "name": "clang-make",
-            "description": "",
+            "displayName": "Makefile + clang + ccache",
-            "displayName": "",
+            "description": "Uses Makefile generator, clang/lld compiler, and ccache",
-            "inherits": []
+            "generator": "Unix Makefiles",
+            "binaryDir": "${sourceDir}/build/${presetName}",
+            "cacheVariables": {
+                "CMAKE_BUILD_TYPE": "Release",
+                "CMAKE_C_COMPILER": "/home/share/micromamba/envs/uLib/bin/clang",
+                "CMAKE_CXX_COMPILER": "/home/share/micromamba/envs/uLib/bin/clang++",
+                "CMAKE_EXE_LINKER_FLAGS": "-fuse-ld=lld",
+                "CMAKE_SHARED_LINKER_FLAGS": "-fuse-ld=lld",
+                "CMAKE_CXX_COMPILER_LAUNCHER": "/home/share/micromamba/envs/uLib/bin/ccache",
+                "CMAKE_C_COMPILER_LAUNCHER": "/home/share/micromamba/envs/uLib/bin/ccache"
+            }
+        },
+        {
+            "name": "cuda",
+            "displayName": "Makefile + clang + ccache",
+            "description": "Uses Makefile generator, clang/lld compiler, and ccache",
+            "generator": "Unix Makefiles",
+            "binaryDir": "${sourceDir}/build/${presetName}",
+            "cacheVariables": {
+                "CMAKE_BUILD_TYPE": "Release",
+                "CMAKE_C_COMPILER": "/home/share/micromamba/envs/uLib/bin/clang",
+                "CMAKE_CXX_COMPILER": "/home/share/micromamba/envs/uLib/bin/clang++",
+                "CMAKE_EXE_LINKER_FLAGS": "-fuse-ld=lld",
+                "CMAKE_SHARED_LINKER_FLAGS": "-fuse-ld=lld",
+                "CMAKE_CXX_COMPILER_LAUNCHER": "/home/share/micromamba/envs/uLib/bin/ccache",
+                "CMAKE_C_COMPILER_LAUNCHER": "/home/share/micromamba/envs/uLib/bin/ccache",
+                "USE_CUDA": "ON"
+            }
         }
     ]
 }

README.md

@@ -88,11 +88,9 @@ micromamba install -n uLib -y clang clangxx lld -c conda-forge
 Then build using the `fast` profile:
 
 ```bash
-conan install . --output-folder=build --build=missing --profile=fast
+conan install . --output-folder=build/clang-ninja --build=missing --profile=fast
-cmake -B build -G Ninja \
+cmake --preset clang-ninja
-      -DCMAKE_TOOLCHAIN_FILE=build/conan_toolchain.cmake \
+cmake --build build/clang-ninja -j$(nproc)
-      -DCMAKE_BUILD_TYPE=Release
-cmake --build build -j$(nproc)
 ```
 
 The `fast` profile is defined at `~/.conan2/profiles/fast` and sets:

app/gcompose/src/ContextModel.cpp

@@ -38,8 +38,8 @@ void ContextModel::setContext(uLib::ObjectsContext* context) {
         });
 
         // Connect existing objects
-        for (auto* obj : m_rootContext->GetObjects()) {
+        for (const auto& obj : m_rootContext->GetObjects()) {
-            uLib::Object::connect(obj, &uLib::Object::Updated, refresh);
+            uLib::Object::connect(obj.get(), &uLib::Object::Updated, refresh);
         }
     }
     endResetModel();
@@ -229,8 +229,8 @@ bool ContextModel::dropMimeData(const QMimeData* data, Qt::DropAction action, in
         [&findAndRemoveRecursive](uLib::Object* current, uLib::Object* target) {
         if (auto ctx = current->GetChildren()) {
             ctx->RemoveObject(target);
-            for (auto* obj : ctx->GetObjects()) {
+            for (const auto& obj : ctx->GetObjects()) {
-                findAndRemoveRecursive(obj, target);
+                findAndRemoveRecursive(obj.get(), target);
             }
         }
     };
@@ -245,9 +245,9 @@ bool ContextModel::dropMimeData(const QMimeData* data, Qt::DropAction action, in
              std::function<bool(uLib::Object*, uLib::Object*)> isDescendant = 
                 [&isDescendant](uLib::Object* root, uLib::Object* target) -> bool {
                   if (auto ctx = root->GetChildren()) {
-                     for (auto* child : ctx->GetObjects()) {
+                      for (const auto& child : ctx->GetObjects()) {
-                         if (child == target) return true;
+                          if (child.get() == target) return true;
-                         if (isDescendant(child, target)) return true;
+                          if (isDescendant(child.get(), target)) return true;
                       }
                   }
                  return false;

app/gcompose/src/ContextPanel.cpp

@@ -90,6 +90,10 @@ void ContextPanel::setContext(uLib::ObjectsContext* context) {
     m_treeView->expandAll();
 }
 
+void ContextPanel::setPropertyContext(uLib::ObjectsContext* context) {
+    m_propertiesPanel->setContext(context);
+}
+
 void ContextPanel::onSelectionChanged(const QItemSelection& selected, const QItemSelection& deselected) {
     uLib::Object* target = nullptr;
     if (!selected.indexes().isEmpty()) {

app/gcompose/src/ContextPanel.h

@@ -20,6 +20,7 @@ public:
     ~ContextPanel();
 
     void setContext(uLib::ObjectsContext* context);
+    void setPropertyContext(uLib::ObjectsContext* context);
     void selectObject(uLib::Object* obj);
     void clearSelection();
 

app/gcompose/src/MainPanel.cpp

@@ -128,6 +128,9 @@ void MainPanel::setContext(uLib::ObjectsContext* context) {
     m_context = context;
     m_contextPanel->setContext(context);
     
+    // Propagate context to all panels for reference property dropdowns
+    m_contextPanel->setPropertyContext(context);
+    m_firstPane->setContext(context);
     if (m_mainVtkContext) {
         if (auto* viewport = qobject_cast<uLib::Vtk::QViewport*>(m_firstPane->currentViewport())) {
             viewport->RemoveProp3D(*m_mainVtkContext);
@@ -179,8 +182,8 @@ void MainPanel::setContext(uLib::ObjectsContext* context) {
 
             // Add any prop3ds that were created during m_mainVtkContext's construction to all panes
             auto panes = this->findChildren<ViewportPane*>();
-            for (auto* obj : context->GetObjects()) {
+            for (const auto& obj : context->GetObjects()) {
-                if (auto* p = m_mainVtkContext->GetProp3D(obj)) {
+                if (auto* p = m_mainVtkContext->GetProp3D(obj.get())) {
                     for (auto* pane : panes) {
                         if (auto* vp = qobject_cast<uLib::Vtk::QViewport*>(pane->currentViewport())) {
                             vp->AddProp3D(*p);

app/gcompose/src/PropertiesPanel.cpp

@@ -47,4 +47,8 @@ void PropertiesPanel::setObject(uLib::Object* obj) {
     m_editor->setObject(obj);
 }
 
+void PropertiesPanel::setContext(uLib::ObjectsContext* context) {
+    m_editor->setContext(context);
+}
+
 PropertiesPanel::~PropertiesPanel() {}

app/gcompose/src/PropertiesPanel.h

@@ -5,6 +5,7 @@
 
 namespace uLib {
     class Object;
+    class ObjectsContext;
     namespace Qt { class PropertyEditor; }
 }
 
@@ -24,6 +25,9 @@ public:
     /** @brief Sets the object to be inspected. */
     void setObject(uLib::Object* obj);
     
+    /** @brief Sets the context for reference property dropdowns. */
+    void setContext(uLib::ObjectsContext* context);
+
 signals:
     void propertyUpdated();
 

app/gcompose/src/PropertyWidgets.cpp

@@ -13,6 +13,7 @@
 #include <QSlider>
 #include <QFontDialog>
 #include "Settings.h"
+#include "Core/ObjectsContext.h"
 
 namespace uLib {
 namespace Qt {
@@ -386,7 +387,74 @@ public:
     }
 };
 
-PropertyEditor::PropertyEditor(QWidget* parent) : QWidget(parent), m_Object(nullptr) {
+////////////////////////////////////////////////////////////////////////////////
+// ReferencePropertyWidget
+
+ReferencePropertyWidget::ReferencePropertyWidget(ReferencePropertyBase* prop, ::uLib::ObjectsContext* context, QWidget* parent)
+    : PropertyWidgetBase(prop, parent), m_RefProp(prop), m_Context(context) {
+    m_Combo = new QComboBox(static_cast<QWidget*>(this));
+    m_Layout->addWidget(m_Combo, 1);
+    refreshCombo();
+    connect(m_Combo, &QComboBox::currentIndexChanged, this, &ReferencePropertyWidget::onComboChanged);
+
+    // Listen for property updates to refresh selected item
+    m_Connection = uLib::Object::connect(prop, &uLib::Object::Updated, [this](){
+        QSignalBlocker blocker(m_Combo);
+        refreshCombo();
+    });
+
+    // Listen for context changes to refresh the dropdown list
+    if (m_Context) {
+        m_ContextConnection = uLib::Object::connect(m_Context, &uLib::Object::Updated, [this](){
+            QSignalBlocker blocker(m_Combo);
+            refreshCombo();
+        });
+    }
+}
+
+ReferencePropertyWidget::~ReferencePropertyWidget() {
+    m_Connection.disconnect();
+    m_ContextConnection.disconnect();
+}
+
+void ReferencePropertyWidget::refreshCombo() {
+    m_Combo->clear();
+    m_Combo->addItem("(none)", QVariant::fromValue((quintptr)0));
+
+    int selectedIdx = 0;
+    Object* currentRef = m_RefProp->GetReferencedObject();
+
+    if (m_Context) {
+        const auto& objects = m_Context->GetObjects();
+        for (const auto& obj : objects) {
+            if (m_RefProp->IsCompatible(obj.get())) {
+                QString label = QString::fromStdString(obj->GetInstanceName());
+                if (label.isEmpty()) {
+                    label = QString::fromStdString(std::string(obj->GetClassName()));
+                }
+                // Add index suffix if name is empty to disambiguate
+                m_Combo->addItem(label, QVariant::fromValue((quintptr)obj.get()));
+                if (obj.get() == currentRef) {
+                    selectedIdx = m_Combo->count() - 1;
+                }
+            }
+        }
+    }
+    m_Combo->setCurrentIndex(selectedIdx);
+}
+
+void ReferencePropertyWidget::onComboChanged(int index) {
+    if (index < 0) return;
+    quintptr ptr = m_Combo->itemData(index).value<quintptr>();
+    Object* obj = reinterpret_cast<Object*>(ptr);
+    m_RefProp->SetReferencedObject(obj);
+    Q_EMIT updated();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// PropertyEditor
+
+PropertyEditor::PropertyEditor(QWidget* parent) : QWidget(parent), m_Object(nullptr), m_Context(nullptr) {
     m_MainLayout = new QVBoxLayout(this);
     m_MainLayout->setContentsMargins(0, 0, 0, 0);
     m_ScrollArea = new QScrollArea(this);
@@ -488,7 +556,11 @@ void PropertyEditor::setObject(::uLib::Object* obj, bool displayOnly) {
                      // widget = new RangePropertyWidget<float>(pflt, m_Container);
                 }
             } else {
-                // Priority 2: Standard factory lookup
+                // Priority 2: Check for reference properties (SmartPointer<T>)
+                if (auto* refProp = dynamic_cast<::uLib::ReferencePropertyBase*>(prop)) {
+                    widget = static_cast<QWidget*>(new ReferencePropertyWidget(refProp, m_Context, m_Container));
+                } else {
+                    // Priority 3: Standard factory lookup
                     auto it = m_Factories.find(prop->GetTypeIndex());
                     if (it != m_Factories.end()) {
                         widget = it->second(prop, m_Container);
@@ -501,6 +573,7 @@ void PropertyEditor::setObject(::uLib::Object* obj, bool displayOnly) {
                         widget->layout()->addWidget(new QLabel("(Read-only: " + QString::fromStdString(prop->GetValueAsString()) + ")"));
                     }
                 }
+            }
 
             if (widget) {
                 if (auto* propWidget = qobject_cast<PropertyWidgetBase*>(widget)) {

app/gcompose/src/PropertyWidgets.h

@@ -4,6 +4,7 @@
 #include <QWidget>
 class QPushButton;
 class QSlider;
+class QComboBox;
 #include <QLabel>
 #include <QHBoxLayout>
 #include <QVBoxLayout>
@@ -21,6 +22,8 @@ class QSlider;
 #include "Math/Dense.h"
 #include "Settings.h"
 
+namespace uLib { class ObjectsContext; }
+
 namespace uLib {
 namespace Qt {
 
@@ -211,12 +214,28 @@ private:
     QPushButton* m_Button;
 };
 
+class ReferencePropertyWidget : public PropertyWidgetBase {
+    Q_OBJECT
+public:
+    ReferencePropertyWidget(ReferencePropertyBase* prop, ::uLib::ObjectsContext* context, QWidget* parent = nullptr);
+    virtual ~ReferencePropertyWidget();
+private slots:
+    void onComboChanged(int index);
+private:
+    void refreshCombo();
+    ReferencePropertyBase* m_RefProp;
+    ::uLib::ObjectsContext* m_Context;
+    QComboBox* m_Combo;
+    Connection m_ContextConnection;
+};
+
 class PropertyEditor : public QWidget {
     Q_OBJECT
 public:
     PropertyEditor(QWidget* parent = nullptr);
     virtual ~PropertyEditor();
     void setObject(uLib::Object* obj, bool displayOnly = false);
+    void setContext(uLib::ObjectsContext* context) { m_Context = context; }
     template<typename T>
     void registerFactory(std::function<QWidget*(PropertyBase*, QWidget*)> factory) {
         m_Factories[std::type_index(typeid(T))] = factory;
@@ -228,6 +247,7 @@ signals:
 private:
     void clear();
     uLib::Object* m_Object;
+    uLib::ObjectsContext* m_Context;
     QVBoxLayout* m_MainLayout;
     QScrollArea* m_ScrollArea;
     QWidget* m_Container;

app/gcompose/src/ViewportPane.cpp

@@ -113,6 +113,10 @@ void ViewportPane::setObject(uLib::Object* obj) {
     }
 }
 
+void ViewportPane::setContext(uLib::ObjectsContext* context) {
+    m_displayEditor->setContext(context);
+}
+
 void ViewportPane::setViewport(QWidget* viewport, const QString& title) {
     if (m_viewport) {
         delete m_viewport;

app/gcompose/src/ViewportPane.h

@@ -7,6 +7,7 @@
 
 namespace uLib {
     class Object;
+    class ObjectsContext;
     namespace Qt { class PropertyEditor; }
     namespace Vtk { class Viewport; }
 }
@@ -30,6 +31,9 @@ public:
     /** @brief Update the display properties for the given object. */
     void setObject(uLib::Object* obj);
     
+    /** @brief Sets the context for reference property dropdowns. */
+    void setContext(uLib::ObjectsContext* context);
+
 private slots:
     void onCloseRequested();
     void showContextMenu(const QPoint& pos);

cmake_output.log

@@ -0,0 +1,217 @@
+-- Using Conan toolchain: /home/rigoni/devel/cmt/uLib/build/clang-make/conan_toolchain.cmake
+-- Conan toolchain: Defining architecture flag: -m64
+-- Conan toolchain: Defining libcxx as C++ flags: -stdlib=libstdc++
+-- Conan toolchain: C++ Standard 17 with extensions ON
+-- The C compiler identification is Clang 21.1.0
+-- The CXX compiler identification is Clang 21.1.0
+-- Detecting C compiler ABI info
+-- Detecting C compiler ABI info - done
+-- Check for working C compiler: /home/share/micromamba/envs/uLib/bin/clang - skipped
+-- Detecting C compile features
+-- Detecting C compile features - done
+-- Detecting CXX compiler ABI info
+-- Detecting CXX compiler ABI info - done
+-- Check for working CXX compiler: /home/share/micromamba/envs/uLib/bin/clang++ - skipped
+-- Detecting CXX compile features
+-- Detecting CXX compile features - done
+-- Project name = uLib
+-- Package name = mutom-0.7
+-- Package version = 0.7
+-- Module path = /home/rigoni/devel/cmt/uLib/CMake;/home/rigoni/devel/cmt/uLib/build/clang-make
+-- CMAKE_PREFIX_PATH is /home/rigoni/devel/cmt/uLib/build/clang-make
+-- Conan: Component target declared 'hdf5::hdf5'
+-- Conan: Component target declared 'hdf5::hdf5_cpp'
+-- Conan: Component target declared 'hdf5::hdf5_hl'
+-- Conan: Component target declared 'hdf5::hdf5_hl_cpp'
+-- Conan: Target declared 'HDF5::HDF5'
+-- Conan: Target declared 'ZLIB::ZLIB'
+-- Conan: Including build module from '/home/rigoni/.conan2/p/b/hdf509daaae89dd98/p/lib/cmake/conan-official-hdf5-variables.cmake'
+-- Conan: Component target declared 'Boost::diagnostic_definitions'
+-- Conan: Component target declared 'Boost::disable_autolinking'
+-- Conan: Component target declared 'Boost::dynamic_linking'
+-- Conan: Component target declared 'Boost::headers'
+-- Conan: Component target declared 'Boost::boost'
+-- Conan: Component target declared 'boost::_libboost'
+-- Conan: Component target declared 'Boost::atomic'
+-- Conan: Component target declared 'Boost::charconv'
+-- Conan: Component target declared 'Boost::container'
+-- Conan: Component target declared 'Boost::context'
+-- Conan: Component target declared 'Boost::date_time'
+-- Conan: Component target declared 'Boost::exception'
+-- Conan: Component target declared 'Boost::math'
+-- Conan: Component target declared 'Boost::program_options'
+-- Conan: Component target declared 'Boost::regex'
+-- Conan: Component target declared 'Boost::serialization'
+-- Conan: Component target declared 'Boost::stacktrace'
+-- Conan: Component target declared 'Boost::system'
+-- Conan: Component target declared 'Boost::timer'
+-- Conan: Component target declared 'Boost::chrono'
+-- Conan: Component target declared 'Boost::coroutine'
+-- Conan: Component target declared 'Boost::filesystem'
+-- Conan: Component target declared 'Boost::json'
+-- Conan: Component target declared 'Boost::math_c99'
+-- Conan: Component target declared 'Boost::math_c99f'
+-- Conan: Component target declared 'Boost::math_c99l'
+-- Conan: Component target declared 'Boost::math_tr1'
+-- Conan: Component target declared 'Boost::math_tr1f'
+-- Conan: Component target declared 'Boost::math_tr1l'
+-- Conan: Component target declared 'Boost::random'
+-- Conan: Component target declared 'Boost::stacktrace_addr2line'
+-- Conan: Component target declared 'Boost::stacktrace_backtrace'
+-- Conan: Component target declared 'Boost::stacktrace_basic'
+-- Conan: Component target declared 'Boost::stacktrace_from_exception'
+-- Conan: Component target declared 'Boost::stacktrace_noop'
+-- Conan: Component target declared 'Boost::test'
+-- Conan: Component target declared 'Boost::url'
+-- Conan: Component target declared 'Boost::wserialization'
+-- Conan: Component target declared 'Boost::fiber'
+-- Conan: Component target declared 'Boost::graph'
+-- Conan: Component target declared 'Boost::iostreams'
+-- Conan: Component target declared 'Boost::nowide'
+-- Conan: Component target declared 'Boost::prg_exec_monitor'
+-- Conan: Component target declared 'Boost::process'
+-- Conan: Component target declared 'Boost::test_exec_monitor'
+-- Conan: Component target declared 'Boost::thread'
+-- Conan: Component target declared 'Boost::wave'
+-- Conan: Component target declared 'Boost::contract'
+-- Conan: Component target declared 'Boost::fiber_numa'
+-- Conan: Component target declared 'Boost::locale'
+-- Conan: Component target declared 'Boost::log'
+-- Conan: Component target declared 'Boost::type_erasure'
+-- Conan: Component target declared 'Boost::unit_test_framework'
+-- Conan: Component target declared 'Boost::log_setup'
+-- Conan: Target declared 'boost::boost'
+-- Conan: Target declared 'BZip2::BZip2'
+-- Conan: Including build module from '/home/rigoni/.conan2/p/b/bzip2b5764e08a4f7d/p/lib/cmake/conan-official-bzip2-variables.cmake'
+-- Conan: Target declared 'libbacktrace::libbacktrace'
+-- Found OpenMP_C: -fopenmp=libomp (found version "5.1")
+-- Found OpenMP_CXX: -fopenmp=libomp (found version "5.1")
+-- Found OpenMP: TRUE (found version "5.1")
+-- Found nlohmann_json: /home/share/micromamba/envs/uLib/share/cmake/nlohmann_json/nlohmann_jsonConfig.cmake (found suitable version "3.12.0", minimum required is "3.12.0")
+-- Found Vdt: /home/share/micromamba/envs/uLib/include (found version "0.4")
+-- Warning: Standard CMAKE_CXX_STANDARD value defined in conan_toolchain.cmake to 17 has been modified to 20 by /home/share/micromamba/envs/uLib/cmake/ROOTUseFile.cmake
+-- Found Python3: /home/share/micromamba/envs/uLib/bin/python3.12 (found suitable version "3.12.13", minimum required is "3.12") found components: Interpreter Development.Module Development.Embed
+-- Found nlohmann_json: /home/share/micromamba/envs/uLib/share/cmake/nlohmann_json/nlohmann_jsonConfig.cmake (found version "3.12.0")
+-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
+-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
+-- Found Threads: TRUE
+-- Performing Test HAVE_STDATOMIC
+-- Performing Test HAVE_STDATOMIC - Success
+-- Found WrapAtomic: TRUE
+-- Found OpenGL: /home/share/micromamba/envs/uLib/lib/libOpenGL.so
+-- Found WrapOpenGL: TRUE
+-- Could NOT find WrapVulkanHeaders (missing: Vulkan_INCLUDE_DIR) 
+-- Found X11: /home/share/micromamba/envs/uLib/include
+-- Looking for XOpenDisplay in /home/share/micromamba/envs/uLib/lib/libX11.so;/home/share/micromamba/envs/uLib/lib/libXext.so
+-- Looking for XOpenDisplay in /home/share/micromamba/envs/uLib/lib/libX11.so;/home/share/micromamba/envs/uLib/lib/libXext.so - found
+-- Looking for gethostbyname
+-- Looking for gethostbyname - found
+-- Looking for connect
+-- Looking for connect - found
+-- Looking for remove
+-- Looking for remove - found
+-- Looking for shmat
+-- Looking for shmat - found
+-- Looking for IceConnectionNumber in ICE
+-- Looking for IceConnectionNumber in ICE - found
+-- Performing Test Iconv_IS_BUILT_IN
+-- Performing Test Iconv_IS_BUILT_IN - Failed
+-- Found Iconv: /home/share/micromamba/envs/uLib/lib/libiconv.so (found version "1.18")
+-- Found ICU: /home/share/micromamba/envs/uLib/include (found version "75.1") found components: data i18n uc
+-- Looking for lzma_auto_decoder in /home/share/micromamba/envs/uLib/lib/liblzma.so
+-- Looking for lzma_auto_decoder in /home/share/micromamba/envs/uLib/lib/liblzma.so - found
+-- Looking for lzma_easy_encoder in /home/share/micromamba/envs/uLib/lib/liblzma.so
+-- Looking for lzma_easy_encoder in /home/share/micromamba/envs/uLib/lib/liblzma.so - found
+-- Looking for lzma_lzma_preset in /home/share/micromamba/envs/uLib/lib/liblzma.so
+-- Looking for lzma_lzma_preset in /home/share/micromamba/envs/uLib/lib/liblzma.so - found
+-- Found LibLZMA: /home/share/micromamba/envs/uLib/lib/liblzma.so (found version "5.8.2")
+-- Conan: Including build module from '/home/rigoni/.conan2/p/b/hdf509daaae89dd98/p/lib/cmake/conan-official-hdf5-variables.cmake'
+-- Found utf8cpp: /home/share/micromamba/envs/uLib/include
+-- Found THEORA: /home/share/micromamba/envs/uLib/lib/libtheora.so
+-- Found OGG: /home/share/micromamba/envs/uLib/lib/libogg.so
+-- Found NetCDF: /home/share/micromamba/envs/uLib/include (found version "4.9.2")
+-- Found JsonCpp: /home/share/micromamba/envs/uLib/lib/libjsoncpp.so (found suitable version "1.9.6", minimum required is "0.7.0")
+-- Found PNG: /home/share/micromamba/envs/uLib/lib/libpng.so (found version "1.6.56")
+-- Found GL2PS: /home/share/micromamba/envs/uLib/lib/libgl2ps.so (found suitable version "1.4.2", minimum required is "1.4.2")
+-- Found LibPROJ: /home/share/micromamba/envs/uLib/lib/libproj.so (found version "9.6.2")
+-- Found SQLite3: /home/share/micromamba/envs/uLib/lib/libsqlite3.so (found version "3.52.0")
+-- Could NOT find WrapVulkanHeaders (missing: Vulkan_INCLUDE_DIR) 
+-- Found LZ4: /home/share/micromamba/envs/uLib/lib/liblz4.so (found version "1.10.0")
+-- Found LZMA: /home/share/micromamba/envs/uLib/lib/liblzma.so (found version "5.8.2")
+-- Found JPEG: /home/share/micromamba/envs/uLib/lib/libjpeg.so (found version "80")
+-- Found TIFF: /home/share/micromamba/envs/uLib/lib/libtiff.so (found version "4.7.1")
+-- Could NOT find freetype (missing: freetype_DIR)
+-- Found Freetype: /home/share/micromamba/envs/uLib/lib/libfreetype.so (found version "2.14.3")
+-- Performing Test HAS_FLTO_THIN
+-- Performing Test HAS_FLTO_THIN - Failed
+-- Performing Test HAS_FLTO_AUTO
+-- Performing Test HAS_FLTO_AUTO - Failed
+-- Performing Test HAS_FLTO
+-- Performing Test HAS_FLTO - Failed
+-- Found pybind11: /home/share/micromamba/envs/uLib/include (found version "3.0.3")
+-- Could NOT find freetype (missing: freetype_DIR)
+CMake Deprecation Warning at /home/share/micromamba/envs/uLib/lib/cmake/Geant4/PTL/PTLConfig.cmake:30 (cmake_minimum_required):
+  Compatibility with CMake < 3.10 will be removed from a future version of
+  CMake.
+
+  Update the VERSION argument <min> value.  Or, use the <min>...<max> syntax
+  to tell CMake that the project requires at least <min> but has been updated
+  to work with policies introduced by <max> or earlier.
+Call Stack (most recent call first):
+  /home/share/micromamba/envs/uLib/share/cmake-4.2/Modules/CMakeFindDependencyMacro.cmake:93 (find_package)
+  /home/share/micromamba/envs/uLib/share/cmake-4.2/Modules/CMakeFindDependencyMacro.cmake:125 (__find_dependency_common)
+  /home/share/micromamba/envs/uLib/lib/cmake/Geant4/Geant4Config.cmake:286 (find_dependency)
+  CMakeLists.txt:194 (find_package)
+
+
+-- Found XercesC: /home/share/micromamba/envs/uLib/lib/libxerces-c.so (found suitable version "3.2.5", minimum required is "3.2.5")
+-- Found Freetype: /home/share/micromamba/envs/uLib/lib/libfreetype.so (found suitable version "2.14.3", minimum required is "2.12.1")
+-- Found Geant4: /home/share/micromamba/envs/uLib/lib/cmake/Geant4/Geant4Config.cmake (found version "11.2.2")
+-- Geant4 libs: Geant4::G4Tree;Geant4::G4FR;Geant4::G4GMocren;Geant4::G4visHepRep;Geant4::G4RayTracer;Geant4::G4VRML;Geant4::G4ToolsSG;Geant4::G4vis_management;Geant4::G4modeling;Geant4::G4interfaces;Geant4::G4mctruth;Geant4::G4geomtext;Geant4::G4gdml;Geant4::G4analysis;Geant4::G4error_propagation;Geant4::G4readout;Geant4::G4physicslists;Geant4::G4run;Geant4::G4event;Geant4::G4tracking;Geant4::G4parmodels;Geant4::G4processes;Geant4::G4digits_hits;Geant4::G4track;Geant4::G4particles;Geant4::G4geometry;Geant4::G4materials;Geant4::G4graphics_reps;Geant4::G4intercoms;Geant4::G4global;Geant4::G4tools;Geant4::G4ptl
+-- Looking for include file inittypes.h
+-- Looking for include file inittypes.h - not found
+-- Looking for include file stdbool.h
+-- Looking for include file stdbool.h - not found
+-- Looking for include file stdint.h
+-- Looking for include file stdint.h - not found
+-- Looking for include file stdlib.h
+-- Looking for include file stdlib.h - not found
+-- Looking for include file dlfcn.h
+-- Looking for include file dlfcn.h - not found
+-- Looking for include file malloc.h
+-- Looking for include file malloc.h - not found
+-- Looking for malloc
+-- Looking for malloc - not found
+-- Looking for include file memory.h
+-- Looking for include file memory.h - not found
+-- Looking for include file math.h
+-- Looking for include file math.h - not found
+-- Looking for fsetround
+-- Looking for fsetround - not found
+-- Looking for floor
+-- Looking for floor - not found
+-- Looking for pow
+-- Looking for pow - not found
+-- Looking for sqrt
+-- Looking for sqrt - not found
+-- Looking for strdup
+-- Looking for strdup - not found
+-- Looking for strstr
+-- Looking for strstr - not found
+-- Looking for include file strings.h
+-- Looking for include file strings.h - not found
+-- Looking for include file string.h
+-- Looking for include file string.h - not found
+-- Looking for include file sys/stat.h
+-- Looking for include file sys/stat.h - not found
+-- Looking for include file sys/types.h
+-- Looking for include file sys/types.h - not found
+-- Looking for include file unistd.h
+-- Looking for include file unistd.h - not found
+-- Looking for include file assert.h
+-- Looking for include file assert.h - not found
+-- Geant4 found: 11.2.2
+-- Found Python3: /home/share/micromamba/envs/uLib/bin/python3.12 (found version "3.12.13") found components: Interpreter
+-- Configuring done (9.2s)
+-- Generating done (1.6s)
+-- Build files have been written to: /home/rigoni/devel/cmt/uLib/build/clang-make

docs/object_context.md

@@ -0,0 +1,36 @@
+# Creating Objects and adding to context
+
+In uLib the context is meant to hold a set of objects and their hierarchy. In addition ObjectFactory is used to create objects from a predefined registry. 
+
+Object context can be thought as a collection of uLib::Object instances. And there exists nested collection of objects if a context is added to another context. A nested context is a Group of elements that appears like a single object in the parent context and a hierarchy of objects inside the tree structure. 
+
+## SmartPointer access
+
+SmartPointer is a class that is used to hold a reference to another object. It is a template class that can be used to hold a reference to any object as a shared_ptr. 
+
+The ObjectContext is responsible to keep track of all the objects that are added to it and to provide a way to access them, but also it holds the SmartPointer instances that point to the objects that are added to it. In this way Objects added to a Context are disposed only when all the references to it are removed.
+For this reason the access to a object context for a Object via Get/Set must be done using the SmartPointer instances.
+
+
+## SmartPointer access
+
+SmartPointer is a class that is used to hold a reference to another object. It is a template class that can be used to hold a reference to any object that is derived from uLib::Object. It is a smart pointer because it will automatically delete the object when it is no longer needed. It is also a smart pointer because it will automatically update the object when it is no longer needed. 
+
+The ObjectContext is responsible to keep track of all the objects that are added to it and to provide a way to access them, but also it holds the SmartPointer instances that point to the objects that are added to it. In this way Objects added to a Context are disposed only when the context is destroyed.
+For this reason the access to a object context for a Object via Get/Set is done using the SmartPointer instances. 
+
+
+## Geant Physical Volumes
+
+The Geant library add a further layer of complexity. The physical volumes are created from a what is called LogicalVolume (which holds information about the shape, material and daughter volumes) and represent the actual instances of the volumes in the detector. So in this sense they represent what could be the Prop3D in the uLib Vtk library. The PhysicalVolume is created from the LogicalVolume and is the one that is actually placed in the scene, with its own relative TRS: position and rotation (rotation here is a rotation matrix comprising the scaling). 
+
+so Adding a Solid or a Logical volume on the scene is not enough. We need to create a PhysicalVolume from the LogicalVolume and add it to the scene to see its instance and apply the TRS to the PhysicalVolume and so to eventually to the representation. 
+
+## Gcompose interaction with objects that have Prop3d and object without 3D actor
+
+In VTK and Qt the objects are organized in a tree structure. When We will add a new object to the scene it will be added to the tree structure and it will be displayed once wrapped in a vtk representation (like vtkContainerBox for instance). 
+
+For objects without 3D representation, they are added to the tree structure but they are not displayed in the scene. But when Object have a internal member that is a reference to another object, this will be represented in the tree structure as a child of the object that contains a reference to it. It is also important to note that the reference can be either the object itself or a smart pointer to the object. So the representation of the child in the tree structure is a placeholder for the object that is referenced and it can be added to many parents, creating multiple instances of the same reference in the tree structure. 
+
+When a object contains a reference to another object, the reference can be set from properties by selecting form the possible instances in the context that are compatible (can be casted) to the type of the reference. 
+In this way the reference appears also as a child in the tree. On the other hand the same add operation can be performed by dragging the object from the tree structure and dropping it on the property of the object that contains the reference. In this case the reference will be set to the parent selecting the compatible menber automatically.

docs/smart_pointer.md

@@ -0,0 +1,120 @@
+# SmartPointer Documentation
+
+`uLib::SmartPointer<T>` is a shared ownership smart pointer implementation designed for the `uLib` ecosystem. While it shares many similarities with `std::shared_ptr`, it includes specific features for legacy compatibility, local reference wrapping, and integrated Boost serialization.
+
+## Table of Contents
+1. [Overview](#overview)
+2. [Key Differences from std::shared_ptr](#key-differences-from-stdshared_ptr)
+3. [Common Usage](#common-usage)
+4. [Construction and Assignment](#construction-and-assignment)
+5. [Wrapping References](#wrapping-references)
+6. [Polymorphism and Casting](#polymorphism-and-casting)
+7. [Serialization](#serialization)
+8. [Thread Safety](#thread-safety)
+
+---
+
+## Overview
+
+A `SmartPointer` manages the lifetime of an object through reference counting. When the last `SmartPointer` owning an object is destroyed or reset, the object is automatically deleted (unless a custom deleter is provided).
+
+The implementation uses an internal `ControlBlock` to manage the reference count and an optional deleter function.
+
+## Key Differences from std::shared_ptr
+
+| Feature | `uLib::SmartPointer<T>` | `std::shared_ptr<T>` |
+| :--- | :--- | :--- |
+| **Default Constructor** | Initializes to `nullptr`. | Initializes to `nullptr`. |
+| **Implicit Conversion** | Implicitly converts from `T*` and to `T*`. | Explicit construction from `T*`, no implicit conversion to `T*`. |
+| **Reference Wrapping** | Direct support for wrapping `T&` with a no-op deleter. | Requires explicit custom deleter `[](T*){}`. |
+| **Serialization** | Built-in Boost.Serialization support. | Requires external serialization helpers. |
+
+> [!NOTE]
+> The default constructor `SmartPointer<T>()` now initializes to `nullptr`, matching standard C++ smart pointer behavior.
+
+## Common Usage
+
+```cpp
+#include "Core/SmartPointer.h"
+
+// 1. Allocation via default constructor (Allocates a new MyObject)
+uLib::SmartPointer<MyObject> ptr; 
+
+// 2. Explicit null pointer
+uLib::SmartPointer<MyObject> null_ptr(nullptr);
+
+// 3. From raw pointer
+uLib::SmartPointer<MyObject> manual_ptr(new MyObject(args));
+
+// 4. Accessing members
+ptr->DoSomething();
+(*ptr).Value = 10;
+
+// 5. Checking validity
+if (ptr) {
+    // ...
+}
+```
+
+## Construction and Assignment
+
+### Allocation and Ownership
+- `SmartPointer()`: Initializes to `nullptr` (Standard behavior).
+- `SmartPointer(nullptr)`: Initializes to null.
+- `SmartPointer(T* ptr)`: Takes ownership of the raw pointer (implicit conversion allowed).
+- `SmartPointer(T& ref)`: Wraps an existing reference with a no-op deleter (implicit conversion allowed).
+- `SmartPointer(T* ptr, Deleter d)`: Takes ownership and uses a custom deleter.
+- `SmartPointer(const SmartPointer* other)`: Creates a copy from a *pointer* to another `SmartPointer`.
+
+### Move and Copy
+- Supports standard copy and move semantics. Move operations transfer ownership without incrementing the reference count.
+
+### Pointer Access
+- `get()` / `Get()`: Returns the underlying raw pointer.
+- `operator T*()`: Implicit conversion to raw pointer (legacy support).
+
+## Wrapping References
+
+The `SmartPointer` can wrap an existing object (e.g., on the stack) without taking ownership:
+
+```cpp
+MyObject stackObj;
+uLib::SmartPointer<MyObject> spt(stackObj); 
+// spt will NOT delete stackObj when it goes out of scope.
+```
+
+## Polymorphism and Casting
+
+`SmartPointer` supports assignment between compatible types (base/derived). For explicit casting, use the following utilities:
+
+- `uLib::static_pointer_cast<T>(ptr)`
+- `uLib::dynamic_pointer_cast<T>(ptr)`
+- `uLib::const_pointer_cast<T>(ptr)`
+- `uLib::reinterpret_pointer_cast<T>(ptr)`
+
+Example:
+```cpp
+uLib::SmartPointer<Derived> derived(new Derived());
+uLib::SmartPointer<Base> base = derived; // Automatic upcast
+
+auto derived2 = uLib::dynamic_pointer_cast<Derived>(base); // Downcast
+```
+
+## Serialization
+
+`SmartPointer` is fully integrated with `boost::serialization`. It tracks `ControlBlock` identity during serialization to ensure that multiple shared pointers to the same object are correctly reconstructed as a single shared instance.
+
+```cpp
+#include <boost/archive/text_oarchive.hpp>
+
+void save(const uLib::SmartPointer<MyObject>& ptr, std::ostream& os) {
+    boost::archive::text_oarchive oa(os);
+    oa << ptr;
+}
+```
+
+## Thread Safety
+
+- The reference count is managed using `std::atomic<uint32_t>`, making the increment/decrement operations thread-safe.
+- **Note**: While the reference counter itself is thread-safe, the object pointed to by the `SmartPointer` is not automatically protected. Standard thread-safety rules for the underlying type `T` apply.
+- Multiple threads can read the same `SmartPointer` concurrently. Concurrent modification (assignment/reset) of the *same* `SmartPointer` instance by different threads requires external synchronization.

src/Core/ObjectsContext.cpp

@@ -8,28 +8,41 @@ ObjectsContext::ObjectsContext() : Object() {}
 ObjectsContext::~ObjectsContext() {}
 
 void ObjectsContext::AddObject(Object* obj) {
-    if (obj && std::find(m_objects.begin(), m_objects.end(), obj) == m_objects.end()) {
+    if (obj) {
-        m_objects.push_back(obj);
+        auto it = std::find_if(m_objects.begin(), m_objects.end(), [obj](const SmartPointer<Object>& sp) {
+            return sp.get() == obj;
+        });
+        if (it == m_objects.end()) {
+            m_objects.push_back(SmartPointer<Object>(obj));
             // Connect child's update to context's update to trigger re-renders
             Object::connect(obj, &Object::Updated, this, &Object::Updated);
             ULIB_SIGNAL_EMIT(ObjectsContext::ObjectAdded, obj);
             this->Updated(); // Signal that the context has been updated
         }
+    }
 }
 
 void ObjectsContext::RemoveObject(Object* obj) {
-    auto it = std::find(m_objects.begin(), m_objects.end(), obj);
+    auto it = std::find_if(m_objects.begin(), m_objects.end(), [obj](const SmartPointer<Object>& sp) {
+        return sp.get() == obj;
+    });
     if (it != m_objects.end()) {
-        Object* removedObj = *it;
+        Object* removedObj = it->get();
-        m_objects.erase(it);
+        // Since we are about to erase it from the vector, if it was the last reference
+        // it would be deleted. We might want to emit the signal BEFORE erasing.
         ULIB_SIGNAL_EMIT(ObjectsContext::ObjectRemoved, removedObj);
+        m_objects.erase(it);
         this->Updated(); // Signal that the context has been updated
     }
 }
 
 void ObjectsContext::Clear() {
     if (!m_objects.empty()) {
-        for (auto obj : m_objects) {
+        // Create a copy of the pointers to emit signals since m_objects might be modified or cleared
+        std::vector<Object*> toRemove;
+        for (const auto& sp : m_objects) toRemove.push_back(sp.get());
+
+        for (auto obj : toRemove) {
             ULIB_SIGNAL_EMIT(ObjectsContext::ObjectRemoved, obj);
         }
         m_objects.clear();
@@ -37,7 +50,7 @@ void ObjectsContext::Clear() {
     }
 }
 
-const std::vector<Object*>& ObjectsContext::GetObjects() const {
+const std::vector<SmartPointer<Object>>& ObjectsContext::GetObjects() const {
     return m_objects;
 }
 
@@ -47,7 +60,7 @@ size_t ObjectsContext::GetCount() const {
 
 Object* ObjectsContext::GetObject(size_t index) const {
     if (index < m_objects.size()) {
-        return m_objects[index];
+        return m_objects[index].get();
     }
     return nullptr;
 }

src/Core/ObjectsContext.h

@@ -2,6 +2,7 @@
 #define U_CORE_OBJECTS_CONTEXT_H
 
 #include "Core/Object.h"
+#include "Core/SmartPointer.h"
 #include <vector>
 
 namespace uLib {
@@ -36,9 +37,9 @@ public:
 
     /**
      * @brief Returns the collection of objects.
-     * @return Const reference to the vector of object pointers.
+     * @return Const reference to the vector of SmartPointer<Object>.
      */
-    const std::vector<Object*>& GetObjects() const;
+    const std::vector<SmartPointer<Object>>& GetObjects() const;
     
     signals:
     /** @brief Signal emitted when an object is added. */
@@ -60,7 +61,7 @@ public:
     Object* GetObject(size_t index) const;
 
 private:
-    std::vector<Object*> m_objects;
+    std::vector<SmartPointer<Object>> m_objects;
 };
 
 } // namespace uLib

src/Core/Property.h

@@ -15,6 +15,15 @@
 #include "Core/Archives.h"
 #include "Core/Signal.h"
 #include "Core/Object.h"
+#include "Core/SmartPointer.h"
+
+// Type traits for detecting SmartPointer<T>
+namespace uLib {
+template<typename T> struct is_smart_pointer : std::false_type {};
+template<typename T> struct is_smart_pointer<SmartPointer<T>> : std::true_type {};
+template<typename T> struct smart_pointer_element { using type = void; };
+template<typename T> struct smart_pointer_element<SmartPointer<T>> { using type = T; };
+} // namespace uLib
 
 namespace uLib {
 
@@ -216,6 +225,109 @@ private:
 
 } // namespace uLib
 
+namespace uLib {
+
+/**
+ * @brief Base class for reference properties (SmartPointer<T> fields).
+ * Provides a type-erased interface for getting/setting object references
+ * and checking type compatibility.
+ */
+class ReferencePropertyBase : public PropertyBase {
+public:
+  virtual ~ReferencePropertyBase() {}
+  virtual Object* GetReferencedObject() const = 0;
+  virtual void SetReferencedObject(Object* obj) = 0;
+  virtual bool IsCompatible(Object* obj) const = 0;
+  virtual const char* GetReferenceTypeName() const = 0;
+};
+
+/**
+ * @brief Typed reference property for SmartPointer<T> fields.
+ * Filters context objects by dynamic_cast compatibility with T.
+ */
+template <typename T>
+class ReferenceProperty : public ReferencePropertyBase {
+public:
+  ReferenceProperty(Object* owner, const std::string& name, SmartPointer<T>& ref,
+                    const std::string& units = "", const std::string& group = "")
+    : m_owner(owner), m_name(name), m_units(units), m_group(group), m_ref(ref), m_ReadOnly(false) {
+      if (m_owner) m_owner->RegisterProperty(this);
+  }
+
+  virtual ~ReferenceProperty() {}
+
+  // PropertyBase interface
+  virtual const std::string& GetName() const override { return m_name; }
+  virtual const char* GetTypeName() const override { return typeid(SmartPointer<T>).name(); }
+  virtual std::type_index GetTypeIndex() const override { return std::type_index(typeid(ReferencePropertyBase)); }
+  virtual const std::string& GetUnits() const override { return m_units; }
+  virtual void SetUnits(const std::string& units) override { m_units = units; }
+  virtual const std::string& GetGroup() const override { return m_group; }
+  virtual void SetGroup(const std::string& group) override { m_group = group; }
+  virtual bool IsReadOnly() const override { return m_ReadOnly; }
+  void SetReadOnly(bool ro) { m_ReadOnly = ro; }
+
+  virtual std::string GetValueAsString() const override {
+    T* ptr = m_ref.Get();
+    if (!ptr) return "(none)";
+    Object* obj = dynamic_cast<Object*>(ptr);
+    if (obj) {
+      std::string iname = obj->GetInstanceName();
+      if (!iname.empty()) return iname;
+      return obj->GetClassName();
+    }
+    return "(set)";
+  }
+
+  // ReferencePropertyBase interface
+  virtual Object* GetReferencedObject() const override {
+    return dynamic_cast<Object*>(m_ref.Get());
+  }
+
+  virtual void SetReferencedObject(Object* obj) override {
+    if (!obj) {
+      m_ref = SmartPointer<T>(nullptr);
+      this->Updated();
+      if (m_owner) m_owner->Updated();
+      return;
+    }
+    T* casted = dynamic_cast<T*>(obj);
+    if (casted) {
+      m_ref = SmartPointer<T>(casted);
+      this->Updated();
+      if (m_owner) m_owner->Updated();
+    }
+  }
+
+  virtual bool IsCompatible(Object* obj) const override {
+    return dynamic_cast<T*>(obj) != nullptr;
+  }
+
+  virtual const char* GetReferenceTypeName() const override {
+    return typeid(T).name();
+  }
+
+  // Serialization stubs
+  virtual void serialize(Archive::xml_oarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::xml_iarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::text_oarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::text_iarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::hrt_oarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::hrt_iarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::log_archive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::property_register_archive & ar, const unsigned int v) override {}
+
+private:
+  Object* m_owner;
+  std::string m_name;
+  std::string m_units;
+  std::string m_group;
+  SmartPointer<T>& m_ref;
+  bool m_ReadOnly;
+};
+
+} // namespace uLib
+
 namespace uLib {
 namespace Archive {
 
@@ -267,7 +379,20 @@ public:
     }
 
     template<class T> void save_property_impl(const char* name, T& val, const char* units, bool hasRange, const T& minVal, const T& maxVal, bool isReadOnly) {
-        if (m_Object) {
+        if (!m_Object) return;
+        if constexpr (is_smart_pointer<T>::value) {
+            // SmartPointer<U> field: create a ReferenceProperty<U> for type-safe selection
+            using ElementT = typename smart_pointer_element<T>::type;
+            auto* p = new ReferenceProperty<ElementT>(m_Object, name, val, units ? units : "", GetCurrentGroup());
+            p->SetReadOnly(isReadOnly);
+            if (m_DisplayOnly) {
+                m_Object->RegisterDisplayProperty(p);
+                Object* obj = m_Object;
+                Object::connect(p, &Object::Updated, [obj]() { obj->Updated(); });
+            } else {
+                m_Object->RegisterDynamicProperty(p);
+            }
+        } else {
             Property<T>* p = new Property<T>(m_Object, name, &val, units ? units : "", GetCurrentGroup());
             set_range_helper(p, hasRange, minVal, maxVal, typename std::is_arithmetic<T>::type());
             p->SetReadOnly(isReadOnly);

src/Core/SmartPointer.h

@@ -3,7 +3,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
   Copyright (c) 2014, Universita' degli Studi di Padova, INFN sez. di Padova
-  All rights reserved
+  All Padua preserved
 
   Authors: Andrea Rigoni Garola < andrea.rigoni@pd.infn.it >
 
@@ -29,96 +29,119 @@
 #include <atomic>
 #include <functional>
 #include <type_traits>
-#include <utility>
-#include <boost/serialization/access.hpp>
-#include <boost/serialization/nvp.hpp>
-#include <boost/serialization/split_member.hpp>
-#include <boost/serialization/vector.hpp>
-#include <boost/serialization/string.hpp>
 
 #include <boost/serialization/access.hpp>
 #include <boost/serialization/nvp.hpp>
+#include <boost/serialization/split_member.hpp>
 
 namespace uLib {
 
 /**
- * @brief A smart pointer implementation inspired by std::shared_ptr.
+ * @brief Internal control block for shared ownership across polymorphic SmartPointers.
- * 
- * Features modernized C++11/14/17 syntax, thread-safe reference counting,
- * move semantics, and support for custom deleters.
- * 
- * NOTE: Default constructor allocates a new T following legacy behavior.
  */
-template <typename T>
+struct ControlBlock {
-class SmartPointer {
+    std::atomic<uint32_t> count;
+    std::function<void()> deleter;
+
+    explicit ControlBlock(uint32_t initial_count = 1) : count(initial_count) {}
+
+private:
+    friend class boost::serialization::access;
+    template <class Archive>
+    void serialize(Archive& ar, const unsigned int /*version*/) {
+        // ControlBlock identity is tracked by Boost via the cb pointer in ReferenceCounter.
+        // We only save the count value.
+        uint32_t c = count.load();
+        ar & boost::serialization::make_nvp("count", c);
+        if constexpr (Archive::is_loading::value) count.store(c);
+    }
+};
+
+/**
+ * @brief A smart pointer implementation inspired by std::shared_ptr.
+ */
+template <typename T> class SmartPointer {
 public:
     using element_type = T;
 
     /**
-     * @brief Default constructor.
+     * @brief Nested reference counter structure. 
-     * Allocates a new T following legacy behavior.
+     * Preserved as a nested template for Boost serialization compatibility.
      */
-    SmartPointer() : m_counter(nullptr) {
+    struct ReferenceCounter {
-        if constexpr (std::is_default_constructible_v<T>) {
+        T* ptr;
-            m_counter = new ReferenceCounter(new T());
+        ControlBlock* cb;
+
+        ReferenceCounter() : ptr(nullptr), cb(nullptr) {}
+        explicit ReferenceCounter(T* p) : ptr(p), cb(new ControlBlock(1)) {
+            cb->deleter = [p]() { delete p; };
         }
+        template <typename D>
+        ReferenceCounter(T* p, D d) : ptr(p), cb(new ControlBlock(1)) {
+            cb->deleter = [p, d]() { d(p); };
         }
 
-    /**
+    private:
-     * @brief Constructor from nullptr.
+        friend class boost::serialization::access;
-     */
+        template <class Archive>
+        void serialize(Archive& ar, const unsigned int /*version*/) {
+            ar & boost::serialization::make_nvp("ptr", ptr);
+            ar & boost::serialization::make_nvp("cb", cb);
+        }
+    };
+
+    SmartPointer() noexcept : m_counter(nullptr) {}
+
     SmartPointer(std::nullptr_t) noexcept : m_counter(nullptr) {}
 
     /**
-     * @brief Constructor from raw pointer.
+     * @brief Constructor from raw pointer (Implicit conversion allowed for legacy compatibility).
      */
-    explicit SmartPointer(T* ptr) : m_counter(nullptr) {
+    SmartPointer(T* ptr) : m_counter(nullptr) {
         if (ptr) m_counter = new ReferenceCounter(ptr);
     }
 
-    /**
-     * @brief Constructor with custom deleter.
-     */
     template <typename D>
     SmartPointer(T* ptr, D deleter) : m_counter(nullptr) {
         if (ptr) m_counter = new ReferenceCounter(ptr, deleter);
     }
 
-    /**
+    SmartPointer(T &ref) : m_counter(new ReferenceCounter(&ref, [](T*){})) { }
-     * @brief Non-owning constructor from reference.
-     * Uses a no-op deleter to ensure the referenced object is not destroyed.
-     */
-    SmartPointer(T &ref) : m_counter(new ReferenceCounter(&ref, [](T*){}, 1)) { }
 
-    /**
-     * @brief Copy constructor.
-     */
     SmartPointer(const SmartPointer& other) noexcept : m_counter(nullptr) {
         acquire(other.m_counter);
     }
 
-    /**
-     * @brief Copy constructor from a pointer to SmartPointer (Legacy support).
-     */
     SmartPointer(const SmartPointer* other) noexcept : m_counter(nullptr) {
         if (other) acquire(other->m_counter);
     }
 
-    /**
+    template <typename U, typename = std::enable_if_t<std::is_convertible_v<U*, T*>>>
-     * @brief Move constructor.
+    SmartPointer(const SmartPointer<U>& other) noexcept : m_counter(nullptr) {
-     */
+        if (other.m_counter) {
+            m_counter = new ReferenceCounter();
+            m_counter->ptr = static_cast<T*>(other.m_counter->ptr);
+            m_counter->cb = other.m_counter->cb;
+            if (m_counter->cb) m_counter->cb->count.fetch_add(1, std::memory_order_relaxed);
+        }
+    }
+
+    template <typename U>
+    SmartPointer(const SmartPointer<U>& other, T* ptr) noexcept : m_counter(nullptr) {
+        if (other.m_counter) {
+            m_counter = new ReferenceCounter();
+            m_counter->ptr = ptr;
+            m_counter->cb = other.m_counter->cb;
+            if (m_counter->cb) m_counter->cb->count.fetch_add(1, std::memory_order_relaxed);
+        }
+    }
+
     SmartPointer(SmartPointer&& other) noexcept : m_counter(other.m_counter) {
         other.m_counter = nullptr;
     }
 
-    /**
+    ~SmartPointer() { release(); }
-     * @brief Virtual destructor.
-     */
-    virtual ~SmartPointer() { release(); }
 
-    /**
-     * @brief Copy assignment.
-     */
     SmartPointer& operator=(const SmartPointer& other) noexcept {
         if (this != &other) {
             release();
@@ -132,9 +155,6 @@ public:
         return *this;
     }
 
-    /**
-     * @brief Move assignment.
-     */
     SmartPointer& operator=(SmartPointer&& other) noexcept {
         if (this != &other) {
             release();
@@ -144,66 +164,26 @@ public:
         return *this;
     }
 
-    /**
-     * @brief Resets the smart pointer to hold a new raw pointer.
-     */
     void reset(T* ptr = nullptr) {
         release();
         if (ptr) m_counter = new ReferenceCounter(ptr);
     }
 
-    /**
-     * @brief Resets the smart pointer with a custom deleter.
-     */
-    template <typename D>
-    void reset(T* ptr, D deleter) {
-        release();
-        if (ptr) m_counter = new ReferenceCounter(ptr, deleter);
-    }
-
-    /**
-     * @brief Swaps contents with another SmartPointer.
-     */
     void swap(SmartPointer& other) noexcept {
         std::swap(m_counter, other.m_counter);
     }
 
-    /**
+    T& operator*() const noexcept { return *(m_counter->ptr); }
-     * @brief Dereference operator.
-     */
-    T& operator*() const noexcept { return *m_counter->ptr; }
-
-    /**
-     * @brief Member access operator.
-     */
     T* operator->() const noexcept { return m_counter->ptr; }
-
-    /**
-     * @brief Returns the raw pointer.
-     */
     T* get() const noexcept { return m_counter ? m_counter->ptr : nullptr; }
     T* Get() const noexcept { return get(); }
-
-    /**
-     * @brief Implicit conversion to raw pointer (legacy compatibility).
-     */
     operator T*() const noexcept { return get(); }
 
-    /**
-     * @brief Returns the number of SmartPointers sharing ownership.
-     */
     uint32_t use_count() const noexcept {
-        return m_counter ? m_counter->count.load(std::memory_order_relaxed) : 0;
+        return (m_counter && m_counter->cb) ? m_counter->cb->count.load(std::memory_order_relaxed) : 0;
     }
 
-    /**
-     * @brief Returns true if this is the only SmartPointer owning the resource.
-     */
     bool unique() const noexcept { return use_count() == 1; }
-
-    /**
-     * @brief Boolean conversion operator.
-     */
     explicit operator bool() const noexcept { return get() != nullptr; }
 
     BOOST_SERIALIZATION_SPLIT_MEMBER()
@@ -217,104 +197,57 @@ public:
     void load(Archive& ar, const unsigned int /*version*/) {
         release();
         ar & boost::serialization::make_nvp("counter", m_counter);
-        if (m_counter) {
+        if (m_counter && m_counter->cb) {
-            m_counter->count.fetch_add(1, std::memory_order_relaxed);
+            m_counter->cb->count.fetch_add(1, std::memory_order_relaxed);
         }
     }
 
 private:
+    template <typename U> friend class SmartPointer;
     friend class boost::serialization::access;
 
-    struct ReferenceCounter {
-        T* ptr;
-        std::atomic<uint32_t> count;
-        std::function<void(T*)> deleter;
-
-        ReferenceCounter(T* p, uint32_t initial_count = 1)
-            : ptr(p), count(initial_count), deleter([](T* ptr_to_del) { delete ptr_to_del; }) {}
-
-        template <typename D>
-        ReferenceCounter(T* p, D d, uint32_t initial_count = 1)
-            : ptr(p), count(initial_count), deleter(d) {}
-
-        ReferenceCounter() 
-            : ptr(nullptr), count(0), deleter([](T* p) { delete p; }) {}
-
-    private:
-        friend class boost::serialization::access;
-        template <class Archive>
-        void serialize(Archive& ar, const unsigned int /*version*/) {
-            ar & boost::serialization::make_nvp("ptr", ptr);
-        }
-    };
-
     ReferenceCounter* m_counter;
 
     void acquire(ReferenceCounter* c) noexcept {
-        m_counter = c;
         if (c) {
-            c->count.fetch_add(1, std::memory_order_relaxed);
+            m_counter = new ReferenceCounter();
+            m_counter->ptr = c->ptr;
+            m_counter->cb = c->cb;
+            if (m_counter->cb) m_counter->cb->count.fetch_add(1, std::memory_order_relaxed);
         }
     }
 
     void release() noexcept {
         if (m_counter) {
-            if (m_counter->count.fetch_sub(1, std::memory_order_acq_rel) == 1) {
+            if (m_counter->cb && m_counter->cb->count.fetch_sub(1, std::memory_order_acq_rel) == 1) {
-                if (m_counter->ptr) {
+                if (m_counter->cb->deleter) m_counter->cb->deleter();
-                    m_counter->deleter(m_counter->ptr);
+                delete m_counter->cb;
             }
             delete m_counter;
-            }
             m_counter = nullptr;
         }
     }
 };
 
-/**
- * @brief Global swap for SmartPointer.
- */
-template <typename T>
-void swap(SmartPointer<T>& a, SmartPointer<T>& b) noexcept {
-    a.swap(b);
-}
-
-/**
- * @brief Equality comparison.
- */
 template <typename T, typename U> 
-bool operator==(const SmartPointer<T>& a, const SmartPointer<U>& b) noexcept {
+SmartPointer<T> static_pointer_cast(const SmartPointer<U>& r) noexcept { 
-    return a.get() == b.get();
+    return SmartPointer<T>(r, static_cast<T*>(r.get())); 
 }
 
-/**
- * @brief Inequality comparison.
- */
 template <typename T, typename U> 
-bool operator!=(const SmartPointer<T>& a, const SmartPointer<U>& b) noexcept {
+SmartPointer<T> dynamic_pointer_cast(const SmartPointer<U>& r) noexcept { 
-    return a.get() != b.get();
+    if (auto p = dynamic_cast<T*>(r.get())) return SmartPointer<T>(r, p);
+    return SmartPointer<T>(nullptr);
 }
 
-/**
+template <typename T, typename U> 
- * @brief Comparison with nullptr.
+SmartPointer<T> const_pointer_cast(const SmartPointer<U>& r) noexcept { 
- */
+    return SmartPointer<T>(r, const_cast<T*>(r.get())); 
-template <typename T>
-bool operator==(const SmartPointer<T>& a, std::nullptr_t) noexcept {
-    return a.get() == nullptr;
 }
 
-template <typename T>
+template <typename T, typename U> 
-bool operator==(std::nullptr_t, const SmartPointer<T>& a) noexcept {
+SmartPointer<T> reinterpret_pointer_cast(const SmartPointer<U>& r) noexcept { 
-    return a.get() == nullptr;
+    return SmartPointer<T>(r, reinterpret_cast<T*>(r.get())); 
-}
-
-template <typename T>
-bool operator!=(const SmartPointer<T>& a, std::nullptr_t) noexcept {
-    return a.get() != nullptr;
-}
-
-template <typename T>
-bool operator!=(std::nullptr_t, const SmartPointer<T>& a) noexcept {
-    return a.get() != nullptr;
 }
 
 } // namespace uLib

src/Core/testing/AffinityTest.cpp

@@ -10,17 +10,52 @@
 
 using namespace uLib;
 
+std::vector<int> GetAvailableCpus() {
+    std::vector<int> available;
+#ifdef __linux__
+    cpu_set_t cpuset;
+    CPU_ZERO(&cpuset);
+    if (sched_getaffinity(0, sizeof(cpu_set_t), &cpuset) == 0) {
+        for (int i = 0; i < CPU_SETSIZE; ++i) {
+            if (CPU_ISSET(i, &cpuset)) {
+                available.push_back(i);
+            }
+        }
+    }
+#endif
+    return available;
+}
+
+class TestThread : public Thread {
+public:
+    void Run() override {
+        Thread::Sleep(200);
+    }
+};
+
 void TestThreadAffinity() {
     std::cout << "Testing Thread Affinity..." << std::endl;
 #ifdef __linux__
-    Thread t;
+    auto available = GetAvailableCpus();
+    if (available.empty()) {
+        std::cout << "  No CPUs available for affinity test, skipping." << std::endl;
+        return;
+    }
+    int target_cpu = available[0];
+    std::cout << "  Using CPU " << target_cpu << std::endl;
+
+    TestThread t;
     t.Start();
-    t.SetAffinity(0); // Bind to CPU 0
+    t.SetAffinity(target_cpu); 
     
     cpu_set_t cpuset;
     CPU_ZERO(&cpuset);
-    pthread_getaffinity_np(t.GetNativeHandle(), sizeof(cpu_set_t), &cpuset);
+    int s = pthread_getaffinity_np(t.GetNativeHandle(), sizeof(cpu_set_t), &cpuset);
-    assert(CPU_ISSET(0, &cpuset));
+    if (s != 0) {
+        std::cerr << "Error: pthread_getaffinity_np failed with code " << s << std::endl;
+        assert(false);
+    }
+    assert(CPU_ISSET(target_cpu, &cpuset));
     
     t.Join();
     std::cout << "  Passed (Thread bound to CPU 0)." << std::endl;
@@ -32,9 +67,15 @@ void TestThreadAffinity() {
 void TestTeamAffinity() {
     std::cout << "Testing Team Affinity..." << std::endl;
 #ifdef __linux__
-#ifdef _OPENMP
+    auto available = GetAvailableCpus();
+    if (available.size() < 2) {
+        std::cout << "  Not enough CPUs available for Team affinity test, skipping." << std::endl;
+        return;
+    }
+    std::vector<int> cpus = {available[0], available[1]};
+    std::cout << "  Using CPUs " << cpus[0] << ", " << cpus[1] << std::endl;
+
     Team team(2);
-    std::vector<int> cpus = {0, 1};
     team.SetAffinity(cpus);
     
     // We check affinity inside a parallel region
@@ -48,7 +89,6 @@ void TestTeamAffinity() {
         assert(CPU_ISSET(expected_cpu, &cpuset));
     }
     std::cout << "  Passed (Team threads bound correctly)." << std::endl;
-#endif
 #else
     std::cout << "  Affinity not supported on this OS, skipping." << std::endl;
 #endif

src/Core/testing/SerializeTest.cpp

@@ -214,7 +214,7 @@ int test_referece_serialization() {
 }
 
 int test_referece_smartpointer_serialization() {
-  SmartPointer<A> a;
+  SmartPointer<A> a(new A());
   a->init_properties();
   {
     C c, c2; c.m_a = a; c2.m_a = a; 

src/Core/testing/SmartPointerTest.cpp

@@ -27,6 +27,7 @@
 
 
 #include <iostream>
+#include "Core/Object.h"
 #include "Core/SmartPointer.h"
 #include "testing-prototype.h"
 
@@ -34,12 +35,12 @@ using namespace uLib;
 
 namespace Test {
 
-struct ObjectMockInterface {
+struct ObjectMockInterface : public Object {
     virtual void PrintValue()=0;
     virtual int& Value()=0;
 };
 
-class ObjectMock : ObjectMockInterface {
+class ObjectMock : public ObjectMockInterface {
     int value;
 public:
     int& Value() { return value; }
@@ -72,13 +73,11 @@ int main () {
         SmartPointer<Test::ObjectMock> spt(new Test::ObjectMock);
         TEST1(test_smpt(spt));
     }
+
+    // TEST NULL POINTER //
     {
         SmartPointer<Test::ObjectMock> spt;
-        TEST1(test_smpt(spt));
+        TEST1(!spt);
-    }
-    {
-        SmartPointer<Test::ObjectMock> spt = new SmartPointer<Test::ObjectMock>;
-        TEST1(test_smpt(spt));
     }
 
     // TAKE REFERENCE //
@@ -88,7 +87,50 @@ int main () {
         TEST1(test_smpt(spt));
     }
 
+    {
+        Test::ObjectMock obj;
+        SmartPointer<Object> spt1 = obj;
+        SmartPointer<Test::ObjectMock> spt2 = obj;
+        SmartPointer<Test::ObjectMockInterface> spt = obj;
+    }
 
+    { 
+      Test::ObjectMock *obj = new Test::ObjectMock; 
+      SmartPointer<Test::ObjectMock> spt(obj); 
+      SmartPointer<Test::ObjectMock> spt2(spt); 
+      SmartPointer<Test::ObjectMock> spt3(spt); 
+      SmartPointer<Test::ObjectMock> spt4(spt2); 
+      spt->Value() = 123;
+      spt2->Value() = 456;
+      spt3->Value() = 789;
+      spt4->Value() = 101112;
+      TEST1(spt->Value() == 101112);
+      TEST1(spt2->Value() == 101112);
+      TEST1(spt3->Value() == 101112);
+      TEST1(spt4->Value() == 101112);
+    }
 
+    {
+      SmartPointer<Test::ObjectMock> spt = new Test::ObjectMock;
+      spt->Value() = 12345;
+      TEST1(spt->Value() == 12345);
+      
+      SmartPointer<Test::ObjectMock> spt2 = spt;
+      TEST1(spt2->Value() == 12345);
+      TEST1(spt.use_count() == 2);
+    }
+
+    {
+      // Using new with custom deleter
+      bool deleted = false;
+      {
+        SmartPointer<int> spt(new int(10), [&](int* p) {
+          deleted = true;
+          delete p;
+        });
+        TEST1(*spt == 10);
+      }
+      TEST1(deleted == true);
+    }
     END_TESTING;
 }

src/HEP/Geant/GeantRegistration.cpp

@@ -12,6 +12,8 @@ ULIB_REGISTER_OBJECT(Material)
 ULIB_REGISTER_OBJECT(Solid)
 ULIB_REGISTER_OBJECT(TessellatedSolid)
 ULIB_REGISTER_OBJECT(BoxSolid)
+ULIB_REGISTER_OBJECT(LogicalVolume)
+ULIB_REGISTER_OBJECT(PhysicalVolume)
 ULIB_REGISTER_OBJECT(Scene)
 ULIB_REGISTER_OBJECT(SkyPlaneEmitterPrimary)
 ULIB_REGISTER_OBJECT(CylinderEmitterPrimary)

src/HEP/Geant/Solid.cpp

@@ -170,14 +170,6 @@ BoxSolid::BoxSolid(const char *name) :
     m_Solid(new G4Box(name, 1, 1, 1))
   {}
 
-BoxSolid::BoxSolid(const char *name, ContainerBox *box) : 
-    Solid(name),
-    m_ContainerBox(box),
-    m_Solid(new G4Box(name, 1, 1, 1)) {
-  if (box) Object::connect(box, &ContainerBox::Updated, this, &BoxSolid::Update);
-  Update();
-}
-
 BoxSolid::BoxSolid(const char *name, SmartPointer<ContainerBox> box) : 
     Solid(name),
     m_ContainerBox(box),

src/HEP/Geant/Solid.h

@@ -96,9 +96,7 @@ public:
     return m_Logical ? m_Logical->GetName().c_str() : m_Name.c_str();
   }
 
-  void SetSolid(Solid *solid) { m_Solid = solid; }
   void SetSolid(SmartPointer<Solid> solid) { m_Solid = solid; }
-  void SetMaterial(Material *material) { m_Material = material; }
   void SetMaterial(SmartPointer<Material> material) { m_Material = material; }
   
   G4LogicalVolume* GetG4LogicalVolume() const { return m_Logical; }
@@ -163,7 +161,7 @@ protected:
 
   G4VPhysicalVolume *m_Physical;
 
-  // ULIB_DECLARE_PROPERTIES(PhysicalVolume)
+  ULIB_DECLARE_PROPERTIES(PhysicalVolume)
 };
 
 
@@ -173,9 +171,11 @@ protected:
 
 
 class TessellatedSolid : public Solid {
-public:
-  uLibTypeMacro(TessellatedSolid, Solid)
 
+  uLibTypeMacro(TessellatedSolid, Solid)
+  ULIB_SERIALIZE_ACCESS
+
+public:
   TessellatedSolid();
   TessellatedSolid(const char *name);
   
@@ -191,6 +191,8 @@ public:
 protected:
   SmartPointer<TriangleMesh> m_Mesh;
   G4TessellatedSolid *m_Solid;
+
+  //ULIB_DECLARE_PROPERTIES(TessellatedSolid)
 };
 
 
@@ -198,12 +200,14 @@ protected:
 //// BOX SOLID /////////////////////////////////////////////////////////////////
 
 class BoxSolid : public Solid {
-public:
+
   uLibTypeMacro(BoxSolid, Solid)
+  ULIB_SERIALIZE_ACCESS
+
+public:  
 
   BoxSolid();
   BoxSolid(const char *name);
-  BoxSolid(const char *name, ContainerBox *box);
   BoxSolid(const char *name, SmartPointer<ContainerBox> box);
   
   virtual G4VSolid* GetG4Solid() const override { return (G4VSolid*)m_Solid; }
@@ -222,6 +226,8 @@ private:
   SmartPointer<ContainerBox> m_ContainerBox;
 
   G4Box *m_Solid;
+  
+  ULIB_DECLARE_PROPERTIES(BoxSolid)
 };
 
 

src/Math/Assembly.cpp

@@ -89,8 +89,8 @@ void Assembly::ComputeBoundingBox() {
     m_BBoxMin = Vector3f(inf, inf, inf);
     m_BBoxMax = Vector3f(-inf, -inf, -inf);
 
-    for (Object *obj : objects) {
+    for (const auto& obj : objects) {
-        if (auto *box = dynamic_cast<ContainerBox *>(obj)) {
+        if (auto *box = dynamic_cast<ContainerBox *>(obj.get())) {
             // ContainerBox: wm is matrix from unit cube [0,1] to local space
             // Since it is parented to 'this', GetMatrix() is sufficient.
             Matrix4f m = box->GetMatrix();
@@ -104,7 +104,7 @@ void Assembly::ComputeBoundingBox() {
                     m_BBoxMax(a) = std::max(m_BBoxMax(a), corner(a));
                 }
             }
-        } else if (auto *cyl = dynamic_cast<Cylinder *>(obj)) {
+        } else if (auto *cyl = dynamic_cast<Cylinder *>(obj.get())) {
             // Cylinder: centered [-1, 1] radial, [-0.5, 0.5] height
             Matrix4f m = cyl->GetMatrix();
             for (int i = 0; i < 8; ++i) {
@@ -117,7 +117,7 @@ void Assembly::ComputeBoundingBox() {
                     m_BBoxMax(a) = std::max(m_BBoxMax(a), corner(a));
                 }
             }
-        } else if (auto *subAsm = dynamic_cast<Assembly *>(obj)) {
+        } else if (auto *subAsm = dynamic_cast<Assembly *>(obj.get())) {
             // Recursive AABB for nested assemblies
             subAsm->ComputeBoundingBox();
             Vector3f subMin, subMax;

src/Math/testing/VoxImageTest.cpp

@@ -89,17 +89,31 @@ int main() {
   }
 
   {
-    VoxImage<TestVoxel> img(Vector3i(4, 4, 4));
+    const int size = 100;
+    VoxImage<TestVoxel> img(Vector3i(size, size, size));
     img.InitVoxels({0.f, 0});
-    for (int i = 0; i < 4; i++) {
+    for (int i = 0; i < size; i++) {
-      for (int j = 0; j < 4; j++) {
+      for (int j = 0; j < size; j++) {
-        for (int k = 0; k < 4; k++) {
+        for (int k = 0; k < size; k++) {
           img[Vector3i(i, j, k)] = {static_cast<float>(i + j + k), 0};
         }
       }
     }
-    img.ExportToVti("./vti_saved.vti", 0, 1);
+    img.ExportToVti("./vti_saved.vti", 0, true); // compressed
-    // img.ImportFromVtkXml("./test_vox_image.vti");
+
+    VoxImage<TestVoxel> imgR(Vector3i(0, 0, 0));
+    imgR.ImportFromVti("./vti_saved.vti", 0);
+    TEST1(img.GetDims() == imgR.GetDims());
+    TEST1(img.GetSpacing() == imgR.GetSpacing());
+    TEST1(img.GetOrigin() == imgR.GetOrigin());
+    TEST1(img.GetPosition() == imgR.GetPosition());
+    for (int i = 0; i < size; i++) {
+      for (int j = 0; j < size; j++) {
+        for (int k = 0; k < size; k++) {
+          TEST1(img[Vector3i(i, j, k)].Value == imgR[Vector3i(i, j, k)].Value);
+        }
+      }
+    }
   }
 
   {

src/Vtk/HEP/Geant/testing/vtkSolidsTest.cpp

@@ -71,10 +71,8 @@ int main(int argc, char** argv) {
     vtkTess.SetColor(0.2, 0.8, 0.2); // Greenish tess
     
     // Position tessellated solid away from box using the PhysicalVolume
-    Matrix4f trans = Matrix4f::Identity();
+    pvTess->SetPosition(Vector3f(5_m, 0, 0));
-    trans.block<3,1>(0,3) = Vector3f(5_m, 0, 0);
+    pvTess->Updated();
-    pvTess->SetMatrix(trans);
-    vtkTess.Update();
 
     std::cout << "..:: Testing vtkSolidsTest ::.." << std::endl;
     std::cout << "Box and Tessellated solids (placed via PhysicalVolumes) initialized." << std::endl;

src/Vtk/Math/testing/vtkAssemblyTest.cpp

@@ -9,17 +9,17 @@
 
 //////////////////////////////////////////////////////////////////////////////*/
 
+#include "Vtk/Math/vtkAssembly.h"
+#include "Math/Units.h"
 #include "Vtk/Math/vtkAssembly.h"
 #include "Vtk/Math/vtkContainerBox.h"
 #include "Vtk/Math/vtkCylinder.h"
-#include "Vtk/Math/vtkAssembly.h"
-#include "Vtk/vtkObjectsContext.h"
 #include "Vtk/uLibVtkViewer.h"
-#include "Math/Units.h"
+#include "Vtk/vtkObjectsContext.h"
 
 #include <vtkActor.h>
-#include <vtkProperty.h>
 #include <vtkPropCollection.h>
+#include <vtkProperty.h>
 
 #include <iostream>
 
@@ -54,19 +54,22 @@ int main(int argc, char **argv) {
   Vtk::Assembly vtkAsm(&assembly);
 
   Vtk::Viewer viewer;
-    vtkAsm.AddToViewer(viewer); // This triggers prop3d creation via ConnectRenderer which eventually calls Prop3D::GetProp
+  vtkAsm.AddToViewer(
+      viewer); // This triggers prop3d creation via ConnectRenderer which
+               // eventually calls Prop3D::GetProp
 
   // Explicitly update to ensure prop3ds exist and are added to assemblies
   vtkAsm.Update();
 
   // Use the child context to find child prop3ds and set colors
-    if (auto* childCtx = vtkAsm.GetChildrenContext()) {
+  if (auto *childCtx = vtkAsm.GetChildrenContext()) {
-        auto setProps = [](Vtk::Prop3D* p, float r, float g, float b) {
+    auto setProps = [](Vtk::Prop3D *p, float r, float g, float b) {
-            if (!p) return;
+      if (!p)
-            vtkPropCollection* props = p->GetProps();
+        return;
+      vtkPropCollection *props = p->GetProps();
       props->InitTraversal();
-            for (int i=0; i < props->GetNumberOfItems(); ++i) {
+      for (int i = 0; i < props->GetNumberOfItems(); ++i) {
-                if (auto* actor = vtkActor::SafeDownCast(props->GetNextProp())) {
+        if (auto *actor = vtkActor::SafeDownCast(props->GetNextProp())) {
           actor->GetProperty()->SetColor(r, g, b);
           actor->GetProperty()->SetRepresentationToSurface();
           actor->GetProperty()->SetOpacity(0.5);
@@ -79,7 +82,8 @@ int main(int argc, char **argv) {
     setProps(childCtx->GetProp3D(&cyl), 0.0, 0.0, 1.0);  // Blue
   }
 
-    std::cout << "Prop3Ds in viewport: " << viewer.getProp3Ds().size() << " (Expected 4: 1 assembly + 3 children)" << std::endl;
+  std::cout << "Prop3Ds in viewport: " << viewer.getProp3Ds().size()
+            << " (Expected 4: 1 assembly + 3 children)" << std::endl;
 
   // ---- 4. Query the bounding box for terminal output ----
   Vector3f bbMin, bbMax;
@@ -91,7 +95,8 @@ int main(int argc, char **argv) {
   std::cout << "==================================================\n";
   std::cout << " vtkAssemblyTest\n";
   std::cout << " 2 boxes + 1 cylinder grouped in an assembly\n";
-    std::cout << "==================================================" << std::endl;
+  std::cout << "=================================================="
+            << std::endl;
 
   if (interactive) {
     viewer.ZoomAuto();

src/Vtk/Math/testing/vtkContainerBoxTest.cpp

@@ -35,9 +35,8 @@ using namespace uLib;
 int main() {
   BEGIN_TESTING(vtk ContainerBox Test);
 
-  {
   ContainerBox* box = new ContainerBox();
-    box->Scale(Vector3f(1_m, 2_m, 1_m));
+  box->SetSize(Vector3f(1_m, 2_m, 1_m));
   box->SetPosition(Vector3f(0, 0, 0));
 
   Vtk::ContainerBox v_box(box);
@@ -46,9 +45,7 @@ int main() {
   v_box.SetRepresentation(Vtk::Prop3D::Surface);
   v_box.SetOpacity(0.5);
   v_box.SetSelectable(true);
-  }
 
-  Vtk::ContainerBox v_box;
   v_box.findOrAddSignal(&Object::Updated)->connect([&v_box]() {
     std::cout << "box updated: "
               << v_box.GetWrapped()->GetWorldPoint(HPoint3f(1, 1, 1)) << std::endl;

src/Vtk/Math/testing/vtkContainerBoxTest2.cpp

@@ -15,7 +15,7 @@ using namespace uLib;
 
 int main() {
     std::cout << "Creating ContainerBox..." << std::endl;
-    ContainerBox* box = new ContainerBox(Vector3f(1.0, 1.0, 1.0)); // 1x1x1 unit box
+    ContainerBox* box = new ContainerBox(Vector3f(1.0_m , 0.5_m, 1.0_m)); // 1x1x1 unit box
     box->SetInstanceName("MyTestBox");
 
     std::cout << "Creating VTK representation..." << std::endl;

src/Vtk/Math/testing/vtkVoxImageInteractiveTest.cpp

@@ -59,9 +59,9 @@ int main(int argc, char **argv) {
 
   // --- Image 1: Spherical Shell ---
   Vector3i dims1(64, 64, 64);
-  VoxImage<Voxel> img1(dims1);
+  VoxImage<Voxel>* img1 = new VoxImage<Voxel>(dims1);
-  img1.SetSpacing(Vector3f(1.0, 1.0, 1.0));
+  img1->SetSpacing(Vector3f(1.0, 1.0, 1.0));
-  img1.SetPosition(Vector3f(-40, -32, -32));
+  img1->SetPosition(Vector3f(-40, -32, -32));
 
   for (int z = 0; z < dims1(2); ++z) {
     for (int y = 0; y < dims1(1); ++y) {
@@ -76,16 +76,16 @@ int main(int argc, char **argv) {
         } else {
           v.Value = 0.0f;
         }
-        img1[Vector3i(x, y, z)] = v;
+        img1->operator[](Vector3i(x, y, z)) = v;
       }
     }
   }
 
   // --- Image 2: Axes Gradient ---
   Vector3i dims2(64, 64, 64);
-  VoxImage<Voxel> img2(dims2);
+  VoxImage<Voxel>* img2 = new VoxImage<Voxel>(dims2);
-  img2.SetSpacing(Vector3f(1.0, 1.0, 1.0));
+  img2->SetSpacing(Vector3f(1.0, 1.0, 1.0));
-  img2.SetPosition(Vector3f(40, -32, -32));
+  img2->SetPosition(Vector3f(40, -32, -32));
 
   for (int z = 0; z < dims2(2); ++z) {
     for (int y = 0; y < dims2(1); ++y) {
@@ -96,15 +96,15 @@ int main(int argc, char **argv) {
             (float(x) / dims2(0) + float(y) / dims2(1) + float(z) / dims2(2)) /
             3.0f;
         v.Value = (40.0f * val) / factor;
-        img2[Vector3i(x, y, z)] = v;
+        img2->operator[](Vector3i(x, y, z)) = v;
       }
     }
   }
 
-  Vtk::VoxImage vtk_img1(&img1);
+  Vtk::VoxImage vtk_img1(img1);
   vtk_img1.setShadingPreset(0);
 
-  Vtk::VoxImage vtk_img2(&img2);
+  Vtk::VoxImage vtk_img2(img2);
   vtk_img2.setShadingPreset(1); // Use Composite without MIP for variety
 
   Vtk::Viewer viewer;

src/Vtk/Math/testing/vtkVoxImageTest.cpp

@@ -40,12 +40,12 @@ BOOST_AUTO_TEST_CASE(vtkVoxImageConstruction) {
   TestVoxel zero = {0, 0};
   TestVoxel nonzero = {5.5f * 1e-6f, 100};
 
-  VoxImage<TestVoxel> img(Vector3i(10, 10, 10));
+  VoxImage<TestVoxel>* img = new VoxImage<TestVoxel>(Vector3i(10, 10, 10));
-  img.SetSpacing(Vector3f(3, 3, 3));
+  img->SetSpacing(Vector3f(3, 3, 3));
-  img.InitVoxels(zero);
+  img->InitVoxels(zero);
-  img[Vector3i(3, 3, 3)] = nonzero;
+  (*img)[Vector3i(3, 3, 3)] = nonzero;
 
-  Vtk::VoxImage vtk_img(&img);
+  Vtk::VoxImage vtk_img(img);
   vtk_img.SaveToXMLFile("test_vtkvoximage.vti");
 
   if (std::getenv("CTEST_PROJECT_NAME") == nullptr) {

src/Vtk/Math/vtkAssembly.cpp

@@ -44,6 +44,10 @@ Assembly::Assembly(uLib::Assembly *content)
 }
 
 Assembly::~Assembly() {
+    if (this->m_model) {
+        Object::disconnect(this->m_model.get(), &uLib::Assembly::Updated,
+                          this, &Assembly::Update);
+    }
     delete m_ChildContext;
     if (m_BBoxActor)  m_BBoxActor->Delete();
     if (m_VtkAsm)     m_VtkAsm->Delete();

src/Vtk/Math/vtkContainerBox.cpp

@@ -38,6 +38,8 @@
 #include <vtkMatrix4x4.h>
 #include <vtkPolyDataMapper.h>
 #include <vtkProperty.h>
+#include <vtkRenderWindow.h>
+#include <vtkRendererCollection.h>
 #include <vtkSmartPointer.h>
 #include <vtkTransform.h>
 
@@ -50,24 +52,33 @@ struct ContainerBoxData {
   vtkSmartPointer<vtkActor> m_Cube;
   vtkSmartPointer<vtkActor> m_Axes;
   vtkSmartPointer<vtkAssembly> m_VtkAsm;
+  vtkSmartPointer<vtkCubeSource> m_CubeSource;
+  vtkSmartPointer<vtkAxes> m_AxesSource;
   uLib::Connection m_UpdateSignal;
 
   ContainerBoxData()
       : m_Cube(vtkSmartPointer<vtkActor>::New()),
         m_Axes(vtkSmartPointer<vtkActor>::New()),
-        m_VtkAsm(vtkSmartPointer<vtkAssembly>::New()) {}
+        m_VtkAsm(vtkSmartPointer<vtkAssembly>::New()),
-  ~ContainerBoxData() {}
+        m_CubeSource(vtkSmartPointer<vtkCubeSource>::New()),
+        m_AxesSource(vtkSmartPointer<vtkAxes>::New()) {}
 };
 
-ContainerBox::ContainerBox(ContainerBox::Content *content)
+ContainerBox::ContainerBox(uLib::ContainerBox *model)
-    : d(new ContainerBoxData()),
+    : Prop3D(), d(new ContainerBoxData()) {
-      ObjectWrapper(content ? content : new Content()) {
+  this->m_model.reset(model);
   this->InstallPipe();
+
   d->m_UpdateSignal = Object::connect(
       this->m_model.get(), &uLib::Object::Updated, this, &ContainerBox::Update);
+  this->Update();
 }
 
-ContainerBox::~ContainerBox() { delete d; }
+ContainerBox::~ContainerBox() {
+  uLib::Object::disconnect(this->m_model.get(), &uLib::Object::Updated, this,
+                           &ContainerBox::Update);
+  delete d;
+}
 
 vtkPolyData *ContainerBox::GetPolyData() const {
   // TODO
@@ -79,17 +90,35 @@ void ContainerBox::Update() {
   if (!this->m_model)
     return;
 
-  vtkProp3D *prop = vtkProp3D::SafeDownCast(this->GetProp());
+  // Update the sources with the model's dimensions.
-  if (prop) {
+  // This makes the "natural" bounds of the actors correct for VTK gizmos.
-    // Apply the full volume matrix (TRS * m_LocalT)
+  Vector3f size = this->m_model->GetSize();
-    vtkNew<vtkMatrix4x4> m;
+  Vector3f origin = this->m_model->GetOrigin();
-    Matrix4fToVtk(this->m_model->GetMatrix(), m);
-    prop->SetUserMatrix(m);
-    prop->Modified();
-  }
 
-  // Delegate rest of update (appearance, render, etc)
+  // HandlerWidget relies on vtkProp3D::GetBounds() to determine the size
-  ConnectionBlock blocker(d->m_UpdateSignal);
+  // and position of its transformation gizmos. Previously, we were applying
+  // the Size of the container using the actor's UserMatrix. While this looks
+  // correct visually, some VTK utilities (including certain internal paths
+  // of GetBounds()) may prioritize the bounding box of the input geometry
+  // (the PolyData) over the UserMatrix. This resulted in the gizmo defaulting
+  // to a 1x1x1 size because the underlying vtkCubeSource was still 1x1x1.
+
+  d->m_CubeSource->SetBounds(origin.x(), origin.x() + size.x(), origin.y(),
+                             origin.y() + size.y(), origin.z(),
+                             origin.z() + size.z());
+  d->m_CubeSource->Update();
+
+  d->m_AxesSource->SetOrigin(origin.x(), origin.y(), origin.z());
+  d->m_AxesSource->SetScaleFactor(std::max({size.x(), size.y(), size.z()}));
+  d->m_AxesSource->Update();
+
+  // Ensure actors have identity UserMatrix since scaling is in the source.
+  d->m_Cube->SetUserMatrix(nullptr);
+  d->m_Axes->SetUserMatrix(nullptr);
+
+  // Delegate the rest of the update (appearance, TR, render, etc) to Prop3D.
+  // Prop3D::Update() applies the "outer" TRS matrix (Position/Rotation/Scaling)
+  // to the assembly.
   this->Prop3D::Update();
 }
 
@@ -98,66 +127,35 @@ void ContainerBox::SyncFromVtk() {
   if (!this->m_model)
     return;
 
-  vtkProp3D *root = this->GetProxyProp();
+  // Sync the "outer" TRS from the assembly's matrix
-  if (!root)
+  this->Prop3D::SyncFromVtk();
-    return;
-
-  // VTK -> Model: Extract new world TRS from proxy, which matches the model's
-  // TRS center
-  vtkMatrix4x4 *rootMat = root->GetUserMatrix();
-  Matrix4f vtkWorld = VtkToMatrix4f(rootMat);
-
-  // Synchronize TRS property members from the updated local matrix
-  this->m_model->FromMatrix(vtkWorld);
-
-  // Since we modified the model, notify observers, but block the loop back to
-  // VTK ConnectionBlock blocker(d->m_UpdateSignal);
-  this->m_model->Updated();
 }
 
 void ContainerBox::InstallPipe() {
   if (!this->m_model)
     return;
-  Content *c = this->m_model;
-
-  // CUBE
-  vtkSmartPointer<vtkCubeSource> cube = vtkSmartPointer<vtkCubeSource>::New();
 
   vtkSmartPointer<vtkPolyDataMapper> mapper =
       vtkSmartPointer<vtkPolyDataMapper>::New();
-  cube->SetBounds(0, 1, 0, 1, 0, 1);
+
-  mapper->SetInputConnection(cube->GetOutputPort());
+  // CUBE //
-  mapper->Update();
+  mapper->SetInputConnection(d->m_CubeSource->GetOutputPort());
   d->m_Cube->SetMapper(mapper);
   d->m_Cube->GetProperty()->SetRepresentationToWireframe();
   d->m_Cube->GetProperty()->SetAmbient(0.7);
 
   // AXES //
-  vtkSmartPointer<vtkAxes> axes = vtkSmartPointer<vtkAxes>::New();
-  axes->SetOrigin(0, 0, 0);
   mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
-  mapper->SetInputConnection(axes->GetOutputPort());
+  mapper->SetInputConnection(d->m_AxesSource->GetOutputPort());
-  mapper->Update();
   d->m_Axes->SetMapper(mapper);
   d->m_Axes->GetProperty()->SetLineWidth(3);
   d->m_Axes->GetProperty()->SetAmbient(0.4);
   d->m_Axes->GetProperty()->SetSpecular(0);
 
-  // PIVOT //
-  axes = vtkSmartPointer<vtkAxes>::New();
-  axes->SetOrigin(0, 0, 0);
-  mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
-  mapper->SetInputConnection(axes->GetOutputPort());
-  mapper->Update();
-
   d->m_VtkAsm->AddPart(d->m_Cube);
   d->m_VtkAsm->AddPart(d->m_Axes);
   this->SetProp(d->m_VtkAsm);
 
-  // vtkProp3D* root = d->m_VtkAsm;
-  // if (root) {
-  //     this->ApplyProp3DTransform(root);
-  // }
   this->Update();
 }
 

src/Vtk/vtkObjectsContext.cpp

@@ -36,6 +36,12 @@ ObjectsContext::ObjectsContext(uLib::ObjectsContext *context)
 }
 
 ObjectsContext::~ObjectsContext() {
+  if (m_Context) {
+    Object::disconnect(m_Context, &uLib::ObjectsContext::ObjectAdded, this,
+                      &ObjectsContext::OnObjectAdded);
+    Object::disconnect(m_Context, &uLib::ObjectsContext::ObjectRemoved, this,
+                      &ObjectsContext::OnObjectRemoved);
+  }
   for (auto const &[obj, prop3d] : m_Prop3Ds) {
     delete prop3d;
   }
@@ -49,8 +55,8 @@ void ObjectsContext::Synchronize() {
   // 1. Identify objects to add and remove
   const auto &objects = m_Context->GetObjects();
   std::map<uLib::Object *, bool> currentObjects;
-  for (auto obj : objects)
+  for (const auto& obj : objects)
-    currentObjects[obj] = true;
+    currentObjects[obj.get()] = true;
 
   // Remove Prop3Ds for objects no longer in context
   for (auto it = m_Prop3Ds.begin(); it != m_Prop3Ds.end();) {
@@ -71,11 +77,11 @@ void ObjectsContext::Synchronize() {
   }
 
   // Add Prop3Ds for new objects
-  for (auto obj : objects) {
+  for (const auto& obj : objects) {
-    if (m_Prop3Ds.find(obj) == m_Prop3Ds.end()) {
+    if (m_Prop3Ds.find(obj.get()) == m_Prop3Ds.end()) {
-      Prop3D *prop3d = this->CreateProp3D(obj);
+      Prop3D *prop3d = this->CreateProp3D(obj.get());
       if (prop3d) {
-        m_Prop3Ds[obj] = prop3d;
+        m_Prop3Ds[obj.get()] = prop3d;
         if (auto *p3d = vtkProp3D::SafeDownCast(prop3d->GetProp()))
           m_Assembly->AddPart(p3d);
         this->Prop3DAdded(prop3d);