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View Full Version : displacment & shadow play (blinn vs mia_material)


Fess
06-25-2009, 08:15 PM
Hello everyone,


I'm doing a piece with some ground displacment via displacment apporximation node & FG with raytraced shadows eminating from a spotlight.

My problem:

I'm getting artifacting on the shadows in the snow depressions with the BLINN.
Using the mia_material, I'm getting a overall better solve regarding FG/shadows etc.

Don't wanna just move on with the mia_material, I need to know WHY the blinn shader is causing artifacting and how to resolve it..........again.
Back when I did my lamp (http://fess.cgsociety.org/gallery/506369/),I had the same freaking problem, but I seemed to have forgotten how to resolve...

Below is render settings used to output both images, and setting for both shaders.

Any input on this is much appreciated.

http://www.mohan-conceptual.com/blinn_shadow_artifacting.jpg




Thanks,
-J

djx
06-26-2009, 04:56 AM
One difference I notice between your mia and blinn settings is the specular/reflection settings. Your blinn specular color is quite bright, then you set the reflectivity to 0.01. So you will get bright specular highlights and low intensity reflections.

But mia, where this seperation of specular and reflection is handled differently, your reflectivity is set to 0.01 (this will also be the specular level) and then your reflection color (which is a multied by the reflectivity) looks like close to black.

So maybe the lack of artifacts in the mia is due to the very low reflection/specular levels.

-- David

Fess
07-04-2009, 06:04 PM
David,

Thanks for the input, I've been so freakin busy......haven't even had time to return to this thread.

-J

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