I’ve been playing around with KHR_materials_volume and KHR_materials_transmission in the sandbox (v5.0.0-alpha.24). I’m running into a rendering issue when I define both a transmissionTexture and a thicknessTexture.
If I remove either one of them (and rely on the transmissionFactor and/or thicknessFactor instead) the rendering artifacts seems to go away.
Here’s an example that demonstrates the issue - this sample defines both the transmissionTexture and the thicknessTexture. The transmission texture is all white (255, 255, 255), so I would expect the sphere to be fully transparent, but that’s not the case.
For reference, here’s a version where I removed the transmissionTexture, which appears to work around the issue:
I’m unable to reproduce this issue using the Khronos glTF sample viewer.