Does vtkMultiVolume always render more discretely compared to vtkVolume?

Support
1

Hi, vtk experts.

My application can render different volumetric datasets.
Currently, I am working with dental CT volume data.

  • First image: Rendered with a single volume renderer, without applying any masking. I used one global Transfer Function (TF) to adjust the whole volume → the result looks smooth.

render_20250904_015512_1to1
render_20250904_015512_1to1771×771 142 KB

  • Second image: Rendered with vtkMultiVolume , where the same volume data was split into multiple volumes, and each was assigned the same transfer function (TF) → the result still looks more discrete compared to using a single volume.
    render_20250904_142303_1to1
    render_20250904_142303_1to1771×771 140 KB

Both cases use the same sampling rate, but the rendering quality is different.
Is there a way to achieve the same smooth rendering effect when using vtkMultiVolume, similar to the single volume renderer?

Environment: Python VTK 9.5.0 with vtkGPUVolumeRayCastMapper.

Any advice would be greatly appreciated. Thanks in advance!