FIX : worldBound

src/IECoreVDB/VDBObject.cpp

@@ -57,11 +57,23 @@ namespace
 template<typename T>
 Imath::Box<Imath::Vec3<T> > worldBound( const openvdb::GridBase *grid, float padding = 0.50f )
 {
-	openvdb::Vec3i min = grid->metaValue<openvdb::Vec3i>( grid->META_FILE_BBOX_MIN );
-	openvdb::Vec3i max = grid->metaValue<openvdb::Vec3i>( grid->META_FILE_BBOX_MAX );
+	openvdb::CoordBBox vdbBbox;
+	try
+	{
+		vdbBbox.min() = openvdb::Coord( grid->metaValue<openvdb::Vec3i>( grid->META_FILE_BBOX_MIN ) );
+		vdbBbox.max() = openvdb::Coord( grid->metaValue<openvdb::Vec3i>( grid->META_FILE_BBOX_MAX ) );
+	}
+	catch( ... )
+	{
+		// If we don't have metadata available, then hopefully it's because the vdb was freshly created and
+		// hasn't been saved to file yet, which should mean it's fully loaded, and we can call
+		// evalActiveVoxelBoundingBox.
+		// \todo : Can we guarantee that every VDB either is loaded, or has metadata?
+		vdbBbox = grid->evalActiveVoxelBoundingBox();
+	}
 
 	openvdb::Vec3d offset = openvdb::Vec3d( padding );
-	openvdb::BBoxd indexBounds = openvdb::BBoxd( min - offset, max + offset );
+	openvdb::BBoxd indexBounds = openvdb::BBoxd( vdbBbox.min() - offset, vdbBbox.max() + offset );
 	openvdb::BBoxd worldBounds = grid->transform().indexToWorld( indexBounds );
 	openvdb::Vec3d minBB = worldBounds.min();
 	openvdb::Vec3d maxBB = worldBounds.max();