Volume rendering options confusing


as a new Paraview user I’m trying to understand the different “volume” rendering options.

It says: : Smart, Ray Cast Only, GPU Volume, OSPray Based,
but I think it really is (should be):

  • Ray Cast Only CPU Based
  • OSPray CPU Based
  • GPU Based

with “Smart” choosing one of the above, depending on… ???

Now, there is another GPU Volume rendering mode offered by NVIDIA’s IndeX plugin, but that seems NOT the same as “GPU Volume”, and can not be selected as a “volume mode” but only through global rendering representation.

Quite confusing, and unfortunately not well documented, or not at all.
Maybe someone more experienced can shed light on it.


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The short answer is that the default settings should be good enough in most instances.

Longer answer: The Smart volume mapper just picks between the GPU and CPU-based ray casting algorithm depending on whether your hardware has a GPU capable of volume rendering (most do). It was provided to make sure there was a fallback volume renderer in case your GPU didn’t support volume rendering. The other options presented let you explicitly pick the GPU or CPU-based algorithms.

The OSPray CPU based volume renderer from Intel is not a choice that can be made by the Smart option. IndeX is a separate representation altogether for technical reasons having to do with it being provided as a plugin.

I agree the presentation of volume rendering algorithms is confusing and should be cleaned up in the future. But the default settings should work for you most of the time.

Thanks for the insights, very helpful for beginners.

I wish this information was directly displayed inside ParaView, for example next to the “volume renderer” choice, as an annotation or similar.

Interestingly, I could not find it in the documentation / ParaView Guide either.