View Full Version : How can I do this? Glass+distorted refraction

06-29-2009, 06:26 AM
Let's say I have a glass sphere in my scene and lines in the backdrop as an example (a regular pattern of some kind, geometry, picture or whatever).

First, what I want to obtain is a render of my scene without the glass appearing in the final image...I want only the distortion of the background through that same glass (so that the shape of the invisible object remains obvious).

Second, the refractive index creates distortion but that's not enough and I'd like to control that distortion shape with procedural nodes.

I'm kind of stuck at this point...I didn't manage to erase the glass (while keeping its results) and I'd like to plug some procedurals into the refraction channel of the dielectric node but there is no such connection available...

I've joined a small picture (made with photoshop) to show the basic idea...

06-29-2009, 07:27 AM
If your 'glass' is completely transparent, and has no reflection or specular highlights, you'll get just the refraction, which is what you want, yes?

You don't need the Dielectric node for this one, just set transparency to 100% and diffuse/reflection/specular to 0% ( just to be sure )

06-29-2009, 09:42 AM
Ah yes, thanks...

I'm bumping on another strange problem though. While texturing the refraction index with procedural layers (the old way) I get "standard" distorted refraction. When using nodes (by plugging that same refraction index channel with procedural nodes) I get some big black areas in the middle of the refraction as a result...

How is this possible? (assuming that I may use some procedural nodes that are not available in standard texture layers).

06-29-2009, 09:58 AM
You want to texture the Bump channel, not Refractive index surely?

06-29-2009, 11:06 AM
That's it! Thank you :)