diff --git a/src/HEP/Detectors/DetectorChamber.cpp b/src/HEP/Detectors/DetectorChamber.cpp
index d093c85..497d4b2 100644
--- a/src/HEP/Detectors/DetectorChamber.cpp
+++ b/src/HEP/Detectors/DetectorChamber.cpp
@@ -6,8 +6,10 @@ namespace uLib {
 MuonEvent DetectorChamber::ProjectMuonEvent(const MuonEvent &muon) const {
   MuonEvent projectedMuon = muon;
 
-  HPoint3f P = m_ProjectionPlane.origin;
-  HVector3f N = m_ProjectionPlane.direction;
+  // Transform the local projection plane to world coordinates
+  HLine3f worldPlane = this->GetWorldProjectionPlane();
+  HPoint3f P = worldPlane.origin;
+  HVector3f N = worldPlane.direction;
 
   HPoint3f X_in = muon.LineIn().origin;
   HPoint3f X_out = muon.LineOut().origin;
diff --git a/src/HEP/Detectors/DetectorChamber.h b/src/HEP/Detectors/DetectorChamber.h
index 248e059..56d71a6 100644
--- a/src/HEP/Detectors/DetectorChamber.h
+++ b/src/HEP/Detectors/DetectorChamber.h
@@ -45,12 +45,30 @@ class DetectorChamber : public ContainerBox {
 
 public:
 
+  DetectorChamber() : BaseClass() {
+    m_ProjectionPlane.origin = HPoint3f(0, 0, 0);
+    m_ProjectionPlane.direction = HVector3f(0, 0, 1);
+  }
+
+  DetectorChamber(const Vector3f &size) : BaseClass(size) {
+    m_ProjectionPlane.origin = HPoint3f(0, 0, 0);
+    m_ProjectionPlane.direction = HVector3f(0, 0, 1);
+  }
+
   // set the plane where muons hit is projected 
-  // to be represented with a direction vector
+  // coordinates are local to the container box
   void SetProjectionPlane(const HLine3f &normal) { m_ProjectionPlane = normal; }
 
   const HLine3f &GetProjectionPlane() const { return m_ProjectionPlane; }
 
+  HLine3f GetWorldProjectionPlane() const {
+    HLine3f worldPlane;
+    Matrix4f M = this->GetWorldMatrix();
+    worldPlane.origin = M * m_ProjectionPlane.origin;
+    worldPlane.direction = M * m_ProjectionPlane.direction;
+    return worldPlane;
+  }
+
   MuonEvent ProjectMuonEvent(const MuonEvent &muon) const;
 
 private:
diff --git a/src/HEP/Detectors/testing/DetectorChamberTest.cpp b/src/HEP/Detectors/testing/DetectorChamberTest.cpp
index d8e6720..c4478bc 100644
--- a/src/HEP/Detectors/testing/DetectorChamberTest.cpp
+++ b/src/HEP/Detectors/testing/DetectorChamberTest.cpp
@@ -116,5 +116,24 @@ int main() {
     bool posOk3 = (projected.LineIn().origin - expectedPos).norm() < 1e-5;
     TEST1(posOk3);
 
+    // Test Case 4: Transformed DetectorChamber
+    DetectorChamber chamber2;
+    chamber2.SetPosition(Vector3f(0, 0, 100)); // Move chamber to z=100
+    // chamber2.GetProjectionPlane has default origin (0,0,0) and direction (0,0,1)
+    // In world coordinates, this plane is at z = 100 + 0 = 100.
+    
+    muon.LineIn().origin = HPoint3f(50, 60, 50); // dist to world plane (z=100) is 50
+    muon.LineOut().origin = HPoint3f(50, 60, 200); // dist to world plane (z=100) is 100
+    
+    projected = chamber2.ProjectMuonEvent(muon);
+    expectedPos = HPoint3f(50, 60, 100);
+    
+    std::cout << "\nTest Case 4: Transformed DetectorChamber (active world matrix)" << std::endl;
+    std::cout << "Projected Position: " << projected.LineIn().origin.transpose() << std::endl;
+    std::cout << "Expected Position:  " << expectedPos.transpose() << std::endl;
+    
+    bool posOk4 = (projected.LineIn().origin - expectedPos).norm() < 1e-5;
+    TEST1(posOk4);
+
     END_TESTING;
 }