WIP: add SD interface.

Simulation/DetSimCore/src/DetectorConstruction.cpp

@@ -63,3 +63,8 @@ DetectorConstruction::Construct() {
     return physiWorld;
 
 }
+
+void
+DetectorConstruction::ConstructSDandField() {
+
+}

Simulation/DetSimCore/src/DetectorConstruction.h

@@ -19,7 +19,8 @@ public:
     DetectorConstruction(ToolHandle<IDetElemTool>& root_elem);
     ~DetectorConstruction();
 public:
-    G4VPhysicalVolume* Construct();
+    G4VPhysicalVolume* Construct() override;
+    void ConstructSDandField() override;
 
 private:
     ToolHandle<IDetElemTool>& m_root_detelem;