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

@@ -21,8 +21,9 @@ namespace blender::render::hydra {
 extern struct CLG_LogRef *LOG_RENDER_HYDRA_SCENE; /* BSD - Blender Scene Delegate */
 
 class BlenderSceneDelegate : public pxr::HdSceneDelegate {
-  friend ObjectData; /* has access to instances */
-  friend MeshData;   /* has access to materials */
+  friend ObjectData;   /* has access to instances */
+  friend MeshData;     /* has access to materials */
+  friend MaterialData; /* has access to objects and instancers */
 
  public:
   enum class EngineType { VIEWPORT = 1, FINAL, PREVIEW };

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

@@ -227,6 +227,13 @@ void InstancerData::update_as_parent()
       prim_id, pxr::HdChangeTracker::AllDirty);
 }
 
+void InstancerData::update_double_sided(MaterialData *mat_data)
+{
+  for (auto &it : mesh_instances_) {
+    it.second.data->update_double_sided(mat_data);
+  }
+}
+
 pxr::SdfPath InstancerData::object_prim_id(Object *object) const
 {
   /* Making id of object in form like <prefix>_<pointer in 16 hex digits format> */

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

@@ -43,6 +43,7 @@ class InstancerData : public ObjectData {
   void check_remove(std::set<std::string> &available_objects);
   void available_materials(std::set<pxr::SdfPath> &paths) const;
   void update_as_parent();
+  void update_double_sided(MaterialData *mat_data);
 
  private:
   pxr::SdfPath object_prim_id(Object *object) const;

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

@@ -125,7 +125,15 @@ void MaterialData::update()
   scene_delegate_->GetRenderIndex().GetChangeTracker().MarkSprimDirty(prim_id,
                                                                       pxr::HdMaterial::AllDirty);
   if (prev_double_sided != double_sided) {
-
+    for (auto &it : scene_delegate_->objects_) {
+      MeshData *m_data = dynamic_cast<MeshData *>(it.second.get());
+      if (m_data) {
+        m_data->update_double_sided(this);
+      }
+    }
+    for (auto &it : scene_delegate_->instancers_) {
+      it.second->update_double_sided(this);
+    }
   }
 }
 

source/blender/render/hydra/scene_delegate/mesh.cc

@@ -119,6 +119,7 @@ bool MeshData::update_visibility()
 {
   bool ret = ObjectData::update_visibility();
   if (ret) {
+    ID_LOG(2, "");
     scene_delegate_->GetRenderIndex().GetChangeTracker().MarkRprimDirty(
         prim_id, pxr::HdChangeTracker::DirtyVisibility);
   }
@@ -172,6 +173,15 @@ bool MeshData::double_sided() const
   return true;
 }
 
+void MeshData::update_double_sided(MaterialData *mat_data)
+{
+  if (mat_data_ == mat_data) {
+    ID_LOG(2, "");
+    scene_delegate_->GetRenderIndex().GetChangeTracker().MarkRprimDirty(
+        prim_id, pxr::HdChangeTracker::DirtyDoubleSided);
+  }
+}
+
 void MeshData::write_mesh(Mesh *mesh)
 {
   face_vertex_counts_.clear();

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

@@ -29,6 +29,7 @@ class MeshData : public ObjectData {
   pxr::HdPrimvarDescriptorVector primvar_descriptors(pxr::HdInterpolation interpolation) const;
   pxr::SdfPath material_id() const;
   bool double_sided() const;
+  void update_double_sided(MaterialData *mat_data);
 
   pxr::HdCullStyle cull_style = pxr::HdCullStyleBackUnlessDoubleSided;