make DD4hepGeometryContext not inhert from GeometryContext

Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepDetectorElement.hpp

@@ -9,6 +9,7 @@
 #pragma once
 
 #include "Acts/Geometry/GeometryContext.hpp"
+#include "Acts/Plugins/DD4hep/DD4hepGeometryContext.hpp"
 #include "Acts/Plugins/TGeo/TGeoDetectorElement.hpp"
 #include "Acts/Utilities/ThrowAssert.hpp"
 
@@ -42,7 +43,7 @@ class DD4hepDetectorElement : public TGeoDetectorElement {
   using DD4hepVolumeID = dd4hep::DDSegmentation::VolumeID;
 
   /// Broadcast the context type
-  using ContextType = GeometryContext;
+  using ContextType = DD4hepGeometryContext;
 
   /// Define a string based story
   using Store = std::map<std::string,
@@ -94,6 +95,11 @@ class DD4hepDetectorElement : public TGeoDetectorElement {
   /// @note This method enables dynamic geometry updates through the context
   const Transform3& transform(const GeometryContext& gctx) const final;
 
+  /// Return the nominal transform
+  ///
+  /// @note This method returns the nominal transform without any alignment
+  const Transform3& nominalTransform() const;
+
  private:
   /// DD4hep detector element
   dd4hep::DetElement m_detElement;

Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepGeometryContext.hpp

@@ -9,7 +9,6 @@
 #pragma once
 
 #include "Acts/Definitions/Algebra.hpp"
-#include "Acts/Geometry/GeometryContext.hpp"
 
 namespace Acts {
 
@@ -19,14 +18,10 @@ class DD4hepDetectorElement;
 ///
 /// @brief DD4hep specific geometry context for alignment handling
 ///
-/// Extends the base GeometryContext to provide DD4hep-specific alignment
-/// capabilities. The context can be active or inactive, controlling whether
-/// alignment corrections should be applied.
-///
 /// @note This context is specifically designed to work with DD4hepDetectorElement
 /// and provides contextual transformations for alignment purposes.
 ///
-class DD4hepGeometryContext : public GeometryContext {
+class DD4hepGeometryContext {
  public:
   /// Explicit inactive constructor
   /// Creates an inactive geometry context that skips alignment corrections

Plugins/DD4hep/src/DD4hepDetectorElement.cpp

@@ -28,10 +28,16 @@ Acts::DD4hepDetectorElement::DD4hepDetectorElement(
 
 const Acts::Transform3& Acts::DD4hepDetectorElement::transform(
     const GeometryContext& gctx) const {
-  const Acts::DD4hepGeometryContext* dd4hepGtx =
-      gctx.maybeGet<DD4hepGeometryContext>();
-  if (dd4hepGtx != nullptr && dd4hepGtx->isActive()) {
-    return dd4hepGtx->contextualTransform(*this);
+  if (gctx.hasValue()) {
+    const DD4hepGeometryContext* dd4hepContext =
+        gctx.maybeGet<DD4hepGeometryContext>();
+    if (dd4hepContext != nullptr && dd4hepContext->isActive()) {
+      return dd4hepContext->contextualTransform(*this);
+    }
   }
-  return TGeoDetectorElement::m_transform;
+  return nominalTransform();
 }
+
+const Acts::Transform3& Acts::DD4hepDetectorElement::nominalTransform() const {
+  return TGeoDetectorElement::m_transform;
+};

Plugins/DD4hep/src/DD4hepGeometryContext.cpp

@@ -13,5 +13,5 @@
 const Acts::Transform3& Acts::DD4hepGeometryContext::contextualTransform(
     const Acts::DD4hepDetectorElement& dElement) const {
   // Use inactive context as the base transformation state
-  return dElement.transform(DD4hepGeometryContext::inactive());
+  return dElement.nominalTransform();
 }