refactor: decouple SmartPointer reference counting

docs/object_context.md

@@ -12,6 +12,14 @@ The ObjectContext is responsible to keep track of all the objects that are added
 For this reason the access to a object context for a Object via Get/Set is 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).