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View Full Version : Help! prman shadow map woes...

playmesumch00ns
01-17-2003, 06:34 PM
I'm rendering with prman through MTOR. When I turn on shadows, the un-shadowed bits of the object get really grainy. The effect is lessened when I turn up the shadow map res to say 2048, but it is still very obvious. Can anyone tell me how to fix this please?

The image below shows the problem: top is without shadows, bottom is with:
a23
01-18-2003, 01:53 AM
try increasing you shadow bias.
this should help.

AndY
Fex
01-20-2003, 04:28 PM
thing too slightly increasing shadowbias helps
try some more shadowsamples like 32 or 64
you don't need so big shadowmaps
1k should fit for
one object..
dflipb
02-05-2003, 05:23 AM
basically what it is doing is trying to shadow the surface itself. by increasing the bias, it is not including the imediate surface points.

http://graphics.stanford.edu/lab/soft/prman/Toolkit/rnotes-3.7.html

about half way down it talks about the shadow bias

Mark
dflipb
02-05-2003, 05:35 AM
basically what it is doing is trying to shadow the surface itself. by increasing the bias, it is not including the imediate surface points.

http://graphics.stanford.edu/lab/soft/prman/Toolkit/rnotes-3.7.html

about half way down it talks about the shadow bias

Mark
mayax
02-07-2003, 01:15 PM
There are several solutions.

1. you can increase shadow bias (but not too high)

2. you can use softshadow

3. if you're using prman 11 & rat 5.5, you can try raytrace shadow with a shadowmap. that will be more fast than pure raytrace shadow and get better results than pure shadowmap
playmesumch00ns
02-09-2003, 01:11 PM
Thanks for the replies guys. Shadow bias didn't really do anything at all. Whacking the shadow samples up to 32 or 64 basically fixed it.

Unfortunately I don't have access to PRMan 11 : sysadmin here still hasn't figured out distributed rendering, much to my chagrin!
NESEL*
02-10-2003, 02:07 PM
The Shadow Bias only create an offset on the shadow.
It displace it, but theres no effect on the quality of the shadow.

The only way i've got a clean shadow was using a regular Shotlight (Not MTOR), or using SoftShadows(CPU intensive).


Is there any another ways using MTOR???



LESEN*
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