I’m finding the default displacement values of +4 amount and -2 shift for Megascans assets makes them appear deformed when rendered in Vray, especially for vegetation. See below for an example. This was recently mentioned in this post but does not seem resolved. Once I disable the displacement map things look correct. As a workaround to get this vegetation asset looking correct I eventually found I could disable the displacement map, unload the texture from the 2-sided material, then reload it back in, leaving the displacement off (which also ends up removing the Sketchup preview texture & replacing it with the Vray logo texture). This is the case on other assets I’ve tested so it’s not just this particular one. So it seems perhaps the default displacement values are too aggressive?
I tried to replicate your results, but wasn’t able to do so.
On my setup, it looks like the displacement is not used when the displaced material is wrapped in a 2sided material. If I use the base material directly, I can see the displacement, but not when using the 2sided. This is surprising.
I tried V-Ray 4.10.02 and 4.20.01. Which version are you using?
Thanks for looking into this. I am using Vray 3.60.03. As I test this further, I’m finding the displacement is an issue even for 1-sided materials; see displacement distortion below for the “cactus” (aka “udugdanfa”) Megascans asset.
Thanks for the Cactus example.
I don’t really understand what Quixel is doing here. The displacement map is mostly a light gray, with values around 200.
A pixel value of 127 will not move the geometry.
A pixel value between 0 and 127 will move the geometry “inside”.
A pixel value between 127 and 255 will move the geometry “outside”.
So if all pixels are above 127 (which is the case here, the whole image is around 200), the displacement will inflate the model. I don’t think this is expected here. Displacement in Megascans assets is supposed to add detail, not change the overall shape.
Chaos Group also replied regarding displacement in TwoSided materials. Basically, we need to apply the “base” (Generic) material to the container group, not the TwoSided one.
Unfortunately, this is not something Transmutr can automate, since there can be more than one materials in the import, but only one material can be applied to a group.