I'm doing quite a bit of rendering with cvex volume procedural shaders (loading VDBs from bgeo using the volumesamplevfile node and doing some vops processing to the incoming position) and was wondering if there are any tricks to get the fastest render out of them? It's quite slow at the moment with volume quality at 0.5 and large VDBs to get nice non noisy images with lots of details.

have you tried using the file-procedural?
i have no houdini in front of me to test, but i could imagine that H13 has support for VDB primitives in the file-procedural



Seb

I would asume its a similar render setup, but I need the cvex one as im adding a procedural volume shader to the VDB at render time.

You can skip the Volume Procedural entirely and just do these operations in the shader. This requires the extra step of expanding your density field to all areas that you want to be shaded but it's more efficient than the Volume Procedural.
So basically your density field acts only as a shading boundary and then you pull in the VDB data and replace the values from the density field with whatever you calculate.

Ok thanks, ill try it in a shader!

So I'm back on this issue after a while!!
So how can I bring in the sdf and densities of the volume to sample in the shader in the same way as a volume sample from file node?

JordanWalsh
So I'm back on this issue after a while!!
So how can I bring in the sdf and densities of the volume to sample in the shader in the same way as a volume sample from file node?

Render that vdb directly,and volume sample from file in shaders (surface shader and light shader and/or disp shader), i think.

Im still not having much luck sampling the volumes in the shader.