Maya Fur Rendering Errors

[dmurph10]

Here is my post I have on CGTalk. http://forums.cgsociety.org/showthre...?f=7&t=1002537

Hello and thanks for looking!



We are having some fur rendering problems in Mental Ray. As you can see the fur renders great except for the black squares in some of our frames and it results in disco hair.



This is how we have the hair layer set up.
Hair: include all geo and lights. Use background shader layer override (set use background shader settings to 0).

We are using this as our frame buffer:
Framebuffer
Date Type: RGBA (Half) 4x16 Bit

We are also rendering it as an OpenEXR

Any help is much appreciated!@@!

[Remydrh]

These are little "NaN" pixels. (Not a Number) Caused sometimes by hair/fur in Maya.

Autodesk is using their own shader for hair and fur and it's old. You would be better served by replacing it with a modern hair shader from someone like Puppet (Pavel)

Here is a good place to start: djx Blog p_HairTK

This should be reported to Autodesk as well.

[haggi]

Exactly, I had something similiar in my own hair shader. I could find out that if I do a mi_vector_dot(), I sometimes get a value larger than 1.0, something like 1.00006784. Then I made a acos() from this value what give a NaN result. So it is possible that the error is something similiar.

[steve]

Few questions,
which Maya version are you using, what type of light illuminates the hair, any indirect lighting enabled ?