CG talk lighting challenge #4

Captain Obvious · Post by **Captain Obvious** » Sat May 20, 2006 4:41 am

Simple test. Texturing isn't done yet, and neither is lighting. I can't get absorbation to work in Kray, unfortunately, limiting the effect of the glass shading... And all those refractions take a LONG time to render! Also, what the heck are those black squares?

Post by **silverlw** » Mon May 22, 2006 8:06 am

Wow that could be an interesting shot when it's done. Is all Glasgeomtry singlesided?
Have you turned off FG reflections/refractions? It looks like that since the glass is pretty dark and it shouldnt. Always leave FG trans/refr on. The squares you see is probably a documented bug that i guess comes from caustics that you have enabled or? Thickness based absorbtion isnt implemented in kray yet.

Captain Obvious · Post by **Captain Obvious** » Mon May 22, 2006 12:07 pm

Reflection/fraction FG rays is turned on. I never turn if off. :p

All surfaces are single-sided.

I didn't use caustics at all.

Thickness-based absorbation is implemented into Kray since the surface thickness gradient works. However, the surface thickness gradient requires air polygons, and air polygons screwed up the refractions.

More images:
http://tegelstenclothes.mememachines.ne ... ttles1.png
http://tegelstenclothes.mememachines.ne ... ttles2.png
http://tegelstenclothes.mememachines.ne ... ttles3.jpg

Janusz Biela · Post by **Janusz Biela** » Mon May 22, 2006 12:12 pm

Very nice material!

Post by **silverlw** » Mon May 22, 2006 5:33 pm

oh and captain, i see you use old 1.611. Try 1.612 wich i dont think have those black little squares bug.

Captain Obvious · Post by **Captain Obvious** » Mon May 22, 2006 9:33 pm

The other images are rendered in 1.612. I updated after the first render.

Thanks, Johny.

Post by **silverlw** » Wed May 31, 2006 10:21 am

[quote="Thickness-based absorbation is implemented into Kray since the surface thickness gradient works. However, the surface thickness gradient requires air polygons, and air polygons screwed up the refractions.

[/quote]

I havent tried surface thickness in Kray...maybe it actually work's but it will defenitely not work with air polys. Kray does it owns calculations to judge refractions in/out properly. I will see if i can find that glas scene and have a try myself or do you have it already converted for everybody to test? Kray is very fast at rendering glas so maybe you should use more photons? If you have too little and high N-values the interpolation can get really slow.

Captain Obvious · Post by **Captain Obvious** » Wed May 31, 2006 3:01 pm

Weird. On a simple test surface, it works just fine without air polygons. In the bottle scene, it didn't work at all... I'll get back to you on this.

Post by **gtanski** » Thu Jul 06, 2006 11:03 am

If I have this scene or other scene with black squares I could fix that easy.

davide · Post by **davide** » Thu Jul 06, 2006 12:09 pm

It happens to me also.
I have check the models and found some 2p polygons...
Hope its help,
Davide

www.kraytracing.com