Thread: rendering transparent object

I sent an email about the broken link. I also figured out my little problem. I had selected "use raytrace" in the transparency main options. After I deselected it I had transparent glass again while raytrace rendering! Thanks all.

Quote: Originally Posted by edecker I sent an email about the broken link. I also figured out my little problem. I had selected "use raytrace" in the transparency main options. After I deselected it I had transparent glass again while raytrace rendering! Thanks all. Yeah that worked for me too but i dont get the refraction from the glass or the caustics which requires raytrace to be activated. I love caustics from EIAS are...

Hi Eric, Try opening your rendered bottle in After Effects (if you have it). If you do, be sure to put a "solid" color layer beneath the bottle so you can see how the transparency is supposed to look. Joe T

There is no way for raytraced transparency to produce a proper alpha channel. The ray must ultimately return some color. If you have After Effects- you may be able to create a virtual green screen by rendering with the proper background color. This color will be visible through the glass, and you should be able to composite using chroma key. Dave

Eric, You might also try adding the background to the 3D scene if that is possible for your shot. That will give you the most realistic refractions through the glass. Another option is a mix of what I'm suggesting and what Dave has suggested. That way you get some refracted items as well as an alpha that you can finesse in the composite. Bill

Could you create a luma matte pass by, say, using a black background and that bottle using a white transparent material with luminance? Later in AE you could derive an alpha from that.

Oh dear! I'll email Phil about that. Ian