Hello,

I'm using Mantra for the first time and I'm having a bit of an issue getting my character's eyes to render correctly. My eyeballs are set up with the usual two pieces of geometry and the outer transparent surface turns the eyeball black. I'm using a principled shader core for the eye exterior with refractions and fake caustics turned on. I also tried using a classic shader core. The interior eye is using a principled shader with a metallic iris and subsurface turned on. I tried turning off the shadows using this tutorial: https://www.youtube.com/watch?v=xd7YMpTMZP8 [www.youtube.com]

Using the method in the video, I was able to get the iris to render correctly, but the eye whites are still black. I feel like there's a setting I'm missing like ray depth that's causing this. Any help would be appreciated, thanks!

It's most likely a ray bias issue. The minimum distance between a refractive surface an the next surface to hit is the ray bias. The default ray bias in mantra is 0.001, which depending on scene scale is probably way too big to capture the gap between eyeball geometry layers.

That was exactly it, thanks!