Hi everyone,

I'm working on rendering whitewater in Karma XPU and I'm trying to achieve a more realistic "wet look," similar to what can be done with the default Houdini whitewater VEX shader.

In a Rebelway tutorial, the instructor demonstrated how to get a nice wet appearance using the default whitewater shader by calculating gradients. This works great, but as that shader is VEX-based, it's not supported in Karma XPU.

I've tried rendering the whitewater in XPU by converting it to a volume and applying an mtlx volume shader. While it renders, the result lacks the wetness and looks quite dry compared to the VEX shader output.

Here are two images to illustrate the difference:

Image 1 (VEX Shader): This shows the desired wet look achieved with the default VEX whitewater shader. (You would ideally link or attach this image here in your forum post)
Image 2 (Karma XPU with mtlx Volume Shader): This is my current result using Karma XPU and an mtlx volume shader. You can see it's missing that wet, clumpy appearance. (You would ideally link or attach this image here in your forum post)
Does anyone have experience or suggestions on how to adjust the mtlx volume shader settings, or perhaps a different approach within Karma XPU, to make the whitewater look more realistic and achieve that wet, almost semi-transparent, clumpy feel where the foam meets the water? Are there specific mtlx nodes or techniques I should be looking into to simulate the effect of varying water absorption or specular breakup that the gradient calculation in the VEX shader might have been providing?

Any advice or pointers would be greatly appreciated!

Thanks!