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

@@ -284,7 +284,7 @@ pxr::SdfPath BlenderSceneDelegate::world_prim_id() const
 
 ObjectData *BlenderSceneDelegate::object_data(pxr::SdfPath const &id) const
 {
-  pxr::SdfPath p_id = (id.GetName().find("SM_") == 0 || id.GetName().find("field_") == 0) ? id.GetParentPath() : id;
+  pxr::SdfPath p_id = (id.GetName().find("SM_") == 0 || id.GetName().find("VF_") == 0) ? id.GetParentPath() : id;
   auto obj_data = objects_.lookup_ptr(p_id);
   if (obj_data) {
     return obj_data->get();

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

@@ -2,7 +2,6 @@
  * Copyright 2011-2022 Blender Foundation */
 
 #include <pxr/imaging/hd/tokens.h>
-#include <pxr/imaging/hd/volume.h>
 #include <pxr/imaging/hd/bprim.h>
 #include <pxr/imaging/hd/volumeFieldSchema.h>
 #include <pxr/usd/usdHydra/tokens.h>
@@ -28,6 +27,15 @@ VolumeData::VolumeData(BlenderSceneDelegate *scene_delegate,
 void VolumeData::init()
 {
   ID_LOG(1, "");
+  Volume *volume = (Volume *)((Object *)this->id)->data;
+  Main *main = CTX_data_main(scene_delegate_->context);
+  if (!BKE_volume_load(volume, main)) {
+    return;
+  }
+  filepath_ = BKE_volume_grids_frame_filepath(volume);
+  if (BKE_volume_is_loaded(volume)) {
+    BKE_volume_unload(volume);
+  }
   write_transform();
 }
 
@@ -53,17 +61,12 @@ void VolumeData::update()
 
 pxr::VtValue VolumeData::get_data(pxr::SdfPath const &id, pxr::TfToken const &key) const
 {  
-  Volume *volume = (Volume *)((Object *)this->id)->data;
-  Main *main = CTX_data_main(scene_delegate_->context);
-  BKE_volume_load(volume, main);
   if (key == pxr::HdVolumeFieldSchemaTokens->filePath) {
-    auto path = BKE_volume_grids_frame_filepath(volume);
-    return pxr::VtValue(pxr::SdfAssetPath(path, path));
+    return pxr::VtValue(pxr::SdfAssetPath(filepath_, filepath_));
   }
   if (key == pxr::HdVolumeFieldSchemaTokens->fieldName) {
     std::string name = id.GetName();
-    auto a = name.substr(name.find("_") + 1);
-    return pxr::VtValue(pxr::TfToken(name.substr(name.find("_") + 1)));
+    return pxr::VtValue(pxr::TfToken(name.substr(name.find("VF_") + 3)));
   }
   if (key == pxr::HdVolumeFieldSchemaTokens->fieldIndex) {
     return pxr::VtValue(0);
@@ -71,7 +74,6 @@ pxr::VtValue VolumeData::get_data(pxr::SdfPath const &id, pxr::TfToken const &ke
   if (key == pxr::UsdHydraTokens->textureMemory) {
     return pxr::VtValue(0.0f);
   }
-  BKE_volume_unload(volume);
   return pxr::VtValue();
 }
 
@@ -82,10 +84,10 @@ bool VolumeData::update_visibility()
 
 pxr::HdVolumeFieldDescriptorVector VolumeData::volume_field_descriptors() const
 {
-  pxr::HdVolumeFieldDescriptorVector volume_field_descriptors;
   Volume *volume = (Volume *)((Object *)id)->data;
   Main *main = CTX_data_main(scene_delegate_->context);
-  if (!BKE_volume_load(volume, main)) {
+
+  if (!BKE_volume_is_loaded(volume) && !BKE_volume_load(volume, main)) {
     return pxr::HdVolumeFieldDescriptorVector();
   }
 
@@ -94,8 +96,7 @@ pxr::HdVolumeFieldDescriptorVector VolumeData::volume_field_descriptors() const
     return pxr::HdVolumeFieldDescriptorVector();
   }
 
-  const std::string grid_path = BKE_volume_grids_frame_filepath(volume);
-
+  pxr::HdVolumeFieldDescriptorVector volume_field_descriptors;
   for (const int i : IndexRange(num_grids)) {
     const VolumeGrid *grid = BKE_volume_grid_get_for_read(volume, i);
     const std::string grid_name = BKE_volume_grid_name(grid);
@@ -103,7 +104,7 @@ pxr::HdVolumeFieldDescriptorVector VolumeData::volume_field_descriptors() const
     pxr::HdVolumeFieldDescriptor desc = pxr::HdVolumeFieldDescriptor(
         pxr::TfToken(grid_name),
         pxr::UsdVolImagingTokens->openvdbAsset,
-        prim_id.AppendElementString("field_" + grid_name));
+        prim_id.AppendElementString("VF_" + grid_name));
     volume_field_descriptors.push_back(desc);
   }
 

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

@@ -25,7 +25,7 @@ class VolumeData : public ObjectData {
   pxr::HdVolumeFieldDescriptorVector volume_field_descriptors() const;
 
  private:
-   ;
+   std::string filepath_;
 };
 
 }  // namespace blender::render::hydra