source/blender/render/hydra/scene_delegate/blender_scene_delegate.h

@@ -21,7 +21,7 @@ namespace blender::render::hydra {
 extern struct CLG_LogRef *LOG_BSD; /* BSD - Blender Scene Delegate */
 
 class BlenderSceneDelegate : public pxr::HdSceneDelegate {
-  friend MeshData;
+  friend MeshData; /* has access to materials_*/
 
  public:
   enum class EngineType { VIEWPORT = 1, FINAL, PREVIEW };

source/blender/render/hydra/scene_delegate/id.h

@@ -12,11 +12,8 @@
 namespace blender::render::hydra {
 
 class BlenderSceneDelegate;
-class InstancerData;
 
 class IdData {
-  friend InstancerData;
-
  public:
   IdData(BlenderSceneDelegate *scene_delegate, ID *id, pxr::SdfPath const &prim_id);
   virtual ~IdData() = default;

source/blender/render/hydra/scene_delegate/instancer.h

@@ -10,8 +10,6 @@
 namespace blender::render::hydra {
 
 class InstancerData : public ObjectData {
-  friend BlenderSceneDelegate;
-
   struct Instance {
     std::unique_ptr<ObjectData> obj_data;
     pxr::VtIntArray indices;

source/blender/render/hydra/scene_delegate/material.h

@@ -13,11 +13,7 @@
 
 namespace blender::render::hydra {
 
-class MeshData;
-
-class MaterialData : IdData {
-  friend MeshData;
-
+class MaterialData : public IdData {
  public:
   MaterialData(BlenderSceneDelegate *scene_delegate,
                Material *material,