Hi,
I'm working on various converters for Substance Designer/Painter, we'd like to provide users the ability to export maps for various renderers.
I made a first one for vray, it works very well and I now want to adapt it to corona.
I first had a problem with the ior texture: in vray the [1, 100] is remapped in the [0, 1] by simply doing 1/ior. It's really convenient as it allows the usage of a texture quite easily. In corona, even if a texture input is supplied for the ior, it seems it's stuck at 1. So I found a work around: I put a "CoronaMix" and made 1 Divided by my "1/ior" texture, to get the ior value back. it works! but it'd just be more convenient if you did the same trick as vray ;)
Another problem: the glossiness. Eventhough you say you have GGX implemented, it looks like you have applied a curve on the glossiness.. It can't produce as rough surfaces as it should when glossiness = 0.
In Substance Designer/Painter, we have implemented GGX without any changes from the paper, Chaos probably did the same because their glossiness really matches ours. But Corona seems very different..
This is the same setup, the material is
- diffuse black
- reflection white
- ior 100
- glossiness 0
- (ggx in vray)
Corona:
Vray: