2 files changed, 33 insertions, 52 deletions

diff --git a/intern/cycles/blender/blender_volume.cpp b/intern/cycles/blender/blender_volume.cpp
index e039d8a4895..48ae5a2c5ae 100644
--- a/intern/cycles/blender/blender_volume.cpp
+++ b/intern/cycles/blender/blender_volume.cpp
@@ -242,13 +242,6 @@ class BlenderVolumeLoader : public VDBImageLoader {
 #endif
   }
 
-  bool equals(const ImageLoader &other) const override
-  {
-    /* TODO: detect multiple volume datablocks with the same filepath. */
-    const BlenderVolumeLoader &other_loader = (const BlenderVolumeLoader &)other;
-    return b_volume == other_loader.b_volume && grid_name == other_loader.grid_name;
-  }
-
   BL::Volume b_volume;
 };
 
@@ -307,25 +300,10 @@ static void sync_volume_object(BL::BlendData &b_data,
   }
 }
 
-/* If the voxel attributes change, we need to rebuild the bounding mesh. */
-static vector<int> get_voxel_image_slots(Mesh *mesh)
-{
-  vector<int> slots;
-  for (const Attribute &attr : mesh->attributes.attributes) {
-    if (attr.element == ATTR_ELEMENT_VOXEL) {
-      slots.push_back(attr.data_voxel().svm_slot());
-    }
-  }
-
-  return slots;
-}
-
 void BlenderSync::sync_volume(BL::Object &b_ob,
                               Volume *volume,
                               const vector<Shader *> &used_shaders)
 {
-  vector<int> old_voxel_slots = get_voxel_image_slots(volume);
-
   volume->clear();
   volume->used_shaders = used_shaders;
 
@@ -342,8 +320,7 @@ void BlenderSync::sync_volume(BL::Object &b_ob,
   }
 
   /* Tag update. */
-  bool rebuild = (old_voxel_slots != get_voxel_image_slots(volume));
-  volume->tag_update(scene, rebuild);
+  volume->tag_update(scene, true);
 }
 
 CCL_NAMESPACE_END
diff --git a/intern/cycles/render/volume.cpp b/intern/cycles/render/volume.cpp
index fcf33a5e50a..9e633b27cc9 100644
--- a/intern/cycles/render/volume.cpp
+++ b/intern/cycles/render/volume.cpp
@@ -495,6 +495,37 @@ void GeometryManager::create_volume_mesh(Volume *volume, Progress &progress)
   string msg = string_printf("Computing Volume Mesh %s", volume->name.c_str());
   progress.set_status("Updating Mesh", msg);
 
+  /* Find shader and compute padding based on volume shader interpolation settings. */
+  Shader *volume_shader = NULL;
+  int pad_size = 0;
+
+  foreach (Shader *shader, volume->used_shaders) {
+    if (!shader->has_volume) {
+      continue;
+    }
+
+    volume_shader = shader;
+
+    if (shader->volume_interpolation_method == VOLUME_INTERPOLATION_LINEAR) {
+      pad_size = max(1, pad_size);
+    }
+    else if (shader->volume_interpolation_method == VOLUME_INTERPOLATION_CUBIC) {
+      pad_size = max(2, pad_size);
+    }
+
+    break;
+  }
+
+  /* Clear existing volume mesh, done here in case we early out due to
+   * empty grid or missing volume shader. */
+  volume->clear();
+  volume->need_update_rebuild = true;
+
+  if (!volume_shader) {
+    return;
+  }
+
+  /* Create volume mesh builder. */
   VolumeMeshBuilder builder;
 
 #ifdef WITH_OPENVDB
@@ -541,35 +572,11 @@ void GeometryManager::create_volume_mesh(Volume *volume, Progress &progress)
   }
 #endif
 
+  /* If nothing to build, early out. */
   if (builder.empty_grid()) {
     return;
   }
 
-  /* Compute padding. */
-  Shader *volume_shader = NULL;
-  int pad_size = 0;
-
-  foreach (Shader *shader, volume->used_shaders) {
-    if (!shader->has_volume) {
-      continue;
-    }
-
-    volume_shader = shader;
-
-    if (shader->volume_interpolation_method == VOLUME_INTERPOLATION_LINEAR) {
-      pad_size = max(1, pad_size);
-    }
-    else if (shader->volume_interpolation_method == VOLUME_INTERPOLATION_CUBIC) {
-      pad_size = max(2, pad_size);
-    }
-
-    break;
-  }
-
-  if (!volume_shader) {
-    return;
-  }
-
   builder.add_padding(pad_size);
 
   /* Slightly offset vertex coordinates to avoid overlapping faces with other
@@ -585,11 +592,8 @@ void GeometryManager::create_volume_mesh(Volume *volume, Progress &progress)
   vector<float3> face_normals;
   builder.create_mesh(vertices, indices, face_normals, face_overlap_avoidance);
 
-  volume->clear();
   volume->reserve_mesh(vertices.size(), indices.size() / 3);
   volume->used_shaders.push_back(volume_shader);
-  volume->need_update = true;
-  volume->need_update_rebuild = true;
 
   for (size_t i = 0; i < vertices.size(); ++i) {
     volume->add_vertex(vertices[i]);