Transparent material renders black only

I’ve been trying to model and texture an eye for several hours and I just don’t get how to setthe cornea so it is transparent. I tried to apply techniques I found in the on-line manal and in the noob topro but It just wont render transparent. I need help. Can anyone explain how to do that?

I found a tutorial on making an eye Pixar way. For the cornea, the tutorial mentions that “SpecTra” should equal 1. Maybe that is what I’m missing but where do I find “SpecTra”?

I used the RayTrans settings for my cornea material. You can check it out in this .blend file if you want:

Katrice’s eyeballs (.ZIP archive)

BTW, I’ve changed a lot of the image textures for use in YafRay, this is an early version from when I was still using the Blender internal renderer. But the cornea hasn’t changed.

u probably are missing where you need to map the texture to alpha, so that the black color maps to alpha 0.

chipmasque,
Thanks for the file. I just reproduced the settings for your cornea on mine and it works.

PapaSmurf,
I’ll take a look back to the tutorial. Maybe I missed that step. Thanks.

Like three people had troubles with alpha textures this week, so I updated this page http://wiki.blender.org/index.php/Manual/Raytraced_Transparency with another example. Hope it helps.

Thank-you for the manual update PapaSmurf