intern/cycles/scene/object.cpp

@@ -344,6 +344,7 @@ float Object::compute_volume_step_size() const
           /* Step size is transformed from voxel to world space. */
           Transform voxel_tfm = tfm;
           if (metadata.use_transform_3d) {
+
             voxel_tfm = tfm * transform_inverse(metadata.transform_3d);
           }
           voxel_step_size = reduce_min(fabs(transform_direction(&voxel_tfm, size)));

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

@@ -7,12 +7,16 @@
 #include <pxr/usd/usdHydra/tokens.h>
 #include <pxr/usd/usdVol/tokens.h>
 #include <pxr/usdImaging/usdVolImaging/tokens.h>
+#include <pxr/base/gf/matrix3d.h>
+#include <pxr/base/gf/rotation.h>
 
 #include "BKE_material.h"
+#include "BKE_object.h"
 #include "BKE_modifier.h"
 #include "BKE_volume.h"
 #include "BLI_index_range.hh"
 #include "BLI_path_util.h"
+#include "BLI_math_rotation.h"
 #include "DNA_fluid_types.h"
 #include "DNA_scene_types.h"
 #include "DNA_volume_types.h"
@@ -50,13 +54,14 @@ bool VolumeData::is_volume_modifier(Object *object)
 void VolumeData::init()
 {
   ID_LOG(1, "");
+  write_transform();
   if (is_volume_modifier((Object *)this->id)) {
     init_from_modifier();
   }
   else {
     init_from_volume();
   }
-  write_transform();
+  
   write_materials();
 }
 
@@ -98,6 +103,7 @@ void VolumeData::update()
   }
   if (id->recalc & ID_RECALC_TRANSFORM) {
     write_transform();
+    assign_volume_transform();
     bits |= pxr::HdChangeTracker::DirtyTransform;
   }
 
@@ -200,6 +206,9 @@ void VolumeData::init_from_modifier()
       object, eModifierType_Fluid);
   filepath_ = get_cached_file_path(volume_modifier->domain->cache_directory,
                                    scene_delegate_->scene->r.cfra);
+
+  assign_volume_transform();
+
   for (auto &grid_name : supported_grids) {
     field_descriptors_.emplace_back(grid_name,
                                     pxr::UsdVolImagingTokens->openvdbAsset,
@@ -232,4 +241,25 @@ void VolumeData::init_from_volume()
   BKE_volume_unload(volume);
 }
 
+void VolumeData::assign_volume_transform() {
+  Object *object = (Object *)this->id;
+  auto mod = pxr::GfMatrix4d(1.0f).SetScale(0.5) *
+             pxr::GfMatrix4d(1.0f).SetTranslate(pxr::GfVec3d(0.5));
+  auto det = mod.GetDeterminant();
+  auto inversed = mod.GetInverse(&det);
+
+  float scale[3] = {0.5f, 0.5f, 0.5f};
+  if (object->scale[0] != 0.0f) {
+    scale[0] = 0.5f / object->scale[0];
+  }
+  if (object->scale[1] != 0.0f) {
+    scale[1] = 0.5f / object->scale[1];
+  }
+  if (object->scale[2] != 0.0f) {
+    scale[2] = 0.5f / object->scale[2];
+  }
+  auto scale_matrix = pxr::GfMatrix4d(1.0f).SetScale(pxr::GfVec3d(scale[0], scale[1], scale[2]));
+  transform = scale_matrix * inversed * transform;
+}
+
 }  // namespace blender::render::hydra

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

@@ -32,6 +32,7 @@ class VolumeData : public ObjectData {
   std::string get_cached_file_path(std::string directory, int frame);
   void init_from_modifier();
   void init_from_volume();
+  void assign_volume_transform();
 
   std::string filepath_;
   pxr::HdVolumeFieldDescriptorVector field_descriptors_;