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single surface glass

Posted: Tue Nov 06, 2007 7:14 pm
by qrk5
can you make a glass material using just a single surface(no thickness)?
I seem to either make it invisible or it is opaque. I can see that using real light it may always require an actual thickness in the model is this
a correct assumption.

Posted: Tue Nov 06, 2007 8:04 pm
by Bubbaloo
If you put a glass material on a single plane, then it will calculate infinite refraction = scary results. Model glass how it is in reality.

You may be able to apply AGS to single plane geometry, I haven't tried it.

glass

Posted: Tue Nov 06, 2007 11:48 pm
by qrk5
thanks babbaloo, thats what I thought might be the case.

Posted: Wed Nov 07, 2007 4:45 pm
by jo
Bubbaloo wrote: You may be able to apply AGS to single plane geometry, I haven't tried it.
I'd like to know the answer.
I applied AGS to a 2 faces glass in an interior render, but it was really long to clean. So I started to think that it's better to have only one polygon: can somebody shortly confirm this?

TIA, Gio

Posted: Wed Nov 07, 2007 5:51 pm
by Mihai
Yes, you can use AGS on single surfaces. AGS has two components, one 'ghost' which renders invisible (transmittance at 255, and ND at 1), and a solid reflective layer to provide reflections, but since this layer doesn't have any transmittance it doesn't refract either, it just bounces off the surface. It just makes reflections, so you don't have to use a solid surface for AGS. If you have refractive materials, then you need a two sided surface so Maxwell knows when light enters and leaves the object to make a proper refraction.

Posted: Wed Nov 07, 2007 7:03 pm
by Bubbaloo
Ok, Mihai, how about this:
Should AGS be used for solid geometry, too?
Any drawbacks to using AGS on a solid instead of a surface?
Thanks!

Posted: Wed Nov 07, 2007 7:45 pm
by jo
Mihai wrote:Yes, you can use AGS on single surfaces. AGS has two components, one 'ghost' which renders invisible (transmittance at 255, and ND at 1), and a solid reflective layer to provide reflections, but since this layer doesn't have any transmittance it doesn't refract either, it just bounces off the surface. It just makes reflections, so you don't have to use a solid surface for AGS. If you have refractive materials, then you need a two sided surface so Maxwell knows when light enters and leaves the object to make a proper refraction.
Thank you Mihai, really helpful!
:D

Ciao, Gio

Posted: Wed Nov 07, 2007 9:34 pm
by Mihai
Bubbaloo wrote: Any drawbacks to using AGS on a solid instead of a surface?
I can't think of any.....perhaps that it can slightly increase rendertime but I'm not sure.