From 4dddd543933ce9d5674b29ff408516022e67d23e Mon Sep 17 00:00:00 2001
From: Brecht Van Lommel <brecht@blender.org>
Date: Wed, 4 Nov 2020 15:50:32 +0100
Subject: Fix T82016: Cycles assert with empty OpenVDB volumes

---
 intern/cycles/render/volume.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/intern/cycles/render/volume.cpp b/intern/cycles/render/volume.cpp
index a8edc04f8a9..fcf33a5e50a 100644
--- a/intern/cycles/render/volume.cpp
+++ b/intern/cycles/render/volume.cpp
@@ -438,10 +438,15 @@ static openvdb::GridBase::ConstPtr openvdb_grid_from_device_texture(device_textu
                                 image_memory->data_width - 1,
                                 image_memory->data_height - 1,
                                 image_memory->data_depth - 1);
+
+  typename GridType::Ptr sparse = GridType::create(ValueType(0.0f));
+  if (dense_bbox.empty()) {
+    return sparse;
+  }
+
   openvdb::tools::Dense<ValueType, openvdb::tools::MemoryLayout::LayoutXYZ> dense(
       dense_bbox, static_cast<ValueType *>(image_memory->host_pointer));
 
-  typename GridType::Ptr sparse = GridType::create(ValueType(0.0f));
   openvdb::tools::copyFromDense(dense, *sparse, ValueType(volume_clipping));
 
   /* #copyFromDense will remove any leaf node that contains constant data and replace it with a
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