diff --git a/components/renderers/cpp/src/normals.cu b/components/renderers/cpp/src/normals.cu
index b6ffc18de0797bf603e03281ec2e225cf3c03046..0a4c12ae897dcb8990c75a591ffa072d0464191b 100644
--- a/components/renderers/cpp/src/normals.cu
+++ b/components/renderers/cpp/src/normals.cu
@@ -76,7 +76,7 @@ void ftl::cuda::normals(ftl::cuda::TextureObject<float4> &output,
 	computeNormals_kernel<<<gridSize, blockSize, 0, stream>>>(temp, input);
     cudaSafeCall( cudaGetLastError() );
 
-    smooth_normals_kernel<1><<<gridSize, blockSize, 0, stream>>>(temp, output, input, 0.04f);
+    smooth_normals_kernel<3><<<gridSize, blockSize, 0, stream>>>(temp, output, input, 0.04f);
     cudaSafeCall( cudaGetLastError() );
 
 #ifdef _DEBUG