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dielectric and colors ...
Posted: Thu Mar 31, 2005 8:08 pm
by wahn
Hi,
maybe someone asked this question already but I can't find what's going wrong
I try to render colored glass and I saw images on this forum so I assume it's possible but I can't make it work. Maybe a Maya problem?
I try to render an image like this:
That was done with Radiance. Here is my first Maxwell test with "Custom" presets, "ND" 1.52, and "Abbe" 160:
No color? Where is it? Each part in the Radiance image got a different dielectric material with a different color. I tried the "crown" preset:
No success
What am I doing wrong? Help, please ...
Cheers,
Jan
Posted: Thu Mar 31, 2005 9:53 pm
by iker
Colored dielectrics works well, can you explain how are you trying to do it wahn?
Posted: Thu Mar 31, 2005 10:41 pm
by tom
solid color for one body is working but you cannot use mapped color for dielectrics yet.
so, you may set them as seperate objects...
Posted: Fri Apr 01, 2005 1:27 pm
by wahn
Well, I try to use the solid color but from within Maya. Maybe that's the problem:
Or does the geometry have to be a solid? I just use a simple rectangle shape instead of a box. Each stripe with a different color was modelled as a separate plane with a separate dielectric material:
What else can go wrong? Maybe some render globals I have to activate?
Thanks,
Jan
Posted: Fri Apr 01, 2005 2:07 pm
by tom
everything must have a volume, there's no plane in real life so in maxwell you know.
model your sections 3D not 2D (give them thickness)
btw/ set abbe 150 and uv=0 for a clear glass as in your radiance example
Posted: Fri Apr 01, 2005 3:48 pm
by wahn
Thank you very much Tom. Seems to work now

Posted: Fri Apr 01, 2005 8:12 pm
by wahn
Posted: Fri Apr 01, 2005 9:44 pm
by tom
first question: how many bounces?
Posted: Sat Apr 02, 2005 5:15 pm
by wahn
# of bounces: 16
Posted: Sat Apr 02, 2005 11:47 pm
by tom
hmm strange... but this was not the result what i was waiting for...

Posted: Wed Apr 06, 2005 12:16 pm
by wahn
Hi,
I changed the perspective a bit, added other elements to the scene, and more light emitting geometry. The reflections start to look alright (after 11 hours) but I'm not sure about the transparency. Will the glass "clear" (get more transparent) if I add more time to the render? I guess the reflections will have less noise but what about the colored shadows? Which caustics settings should I use?
Cheers,
Jan
Posted: Fri Apr 29, 2005 5:26 pm
by wahn
Hi,
I start to get some colored shadows on the wall
Cheers,
Jan
Posted: Tue Jun 28, 2005 12:15 pm
by wahn
Hi,
I played around a bit with mental ray and the same tapestry (made of dielectric material) to throw photons at it and see what pattern I would get on the wall. I removed the rest of the scene but the pattern on the wall looks much more interesting as with Maxwell. I'm wondering what's more appropriate and maybe someone like Tom could create a similar test?
Here is the tapestry from the front (rendered with mental ray):
The caustics are created by 4 spotlights. They are at the same position as in the Maxwell images. Three in the back (in the same row) and one in front. Here is another view where you can see the light positions:
Maybe there are too many other lights in the Maxwell scene to show that kind of effect. Can someone create a scene for Maxwell which show a similar pattern on the back wall? Or is the result I get with mental ray wrong?
Cheers,
Jan