Refractive Materials?

Chris Bruin

I am attempting to create an eye in TB2, I have 2 shells, the inner eye (solid), and the outer shell of the eye (transparent, Transparency set to additive). Under the Reflectivity part of the material, I have it set to Refractive Index, with an index set to 1.5 (approximately a human eye).

However, nothing happens, as seen here:


Is there a way to mimic a dielectric material in TB2? I assume I'm doing something wrong, as this seems fairly straight forward to setup and it's not working how I would expect it to based on my settings.

Thanks!

EarthQuake

First off, I think its important to explain a couple terms:

1. Index of refraction is a method to set base reflectivity or specular intensity, similar to the spec map or metalness map input workflows. For IOR, you can used measure scientifically accurate values based on the IOR scale. It looks like the value would be about 1.41 for the lens of the eye.

From your image, everything appears to be working correctly here. IOR is not something that would generally be used for games though.

2. Refraction, or how an object's properties (in this case the lens of the eye) distort another object behind it (the eyeball itself) is something entirely different. Unfortunately we have not yet added a refraction shader to TB2. This is something we will likely add in the future.

A work around that I found works very well is to have both the inner and outeye eyeball shapes match, and then use the parallax mapping feature to fake the refraction.

You can change the normal map slot to parallax map, and then load a height map to control the effect.



Here is an example scene: https://dl.dropboxusercontent.com/u/499159/toolbag2eyes01.zip



I hope this helps.