Grain on black (dark) shaders

[igordesign]

HI friends, i lighting a 3D car, and i have problens to set up my scene because on dark shaders have many grain (noise) in this objects.
Other shaders appears normal, only dark shaders are bad.

I'm using LC + BF to Gi, adaptive 1 and 25, overwrite enviroment with hdrs and on gi blured hdr.

Settings:
http://www.igorvfx.com/forum/vray/settings.jpg

Render:
Beauty - http://www.igorvfx.com/forum/vray/beauty.jpg
GI - http://www.igorvfx.com/forum/vray/gi.jpg
reflect - http://www.igorvfx.com/forum/vray/reflect.jpg

I have 8 rectLights on top of the scene with 32 subds.

could someone help me please?

[georgi.zhekov]

Hello,

What about your lighting pass? In some cases 32 subdivisions for the lights is too low. From what I see the GI pass is causing a fair amount of noise - you can try and tweak it with a bit more subdivs, changing the Threshold value to 0.005 or a bit lower might help as well.

[igordesign]

Thanks friend, i'll try and post the results here.
Thanks!

[vlado]

Can you show me your "color mapping" settings?

Best regards,
Vlado

[igordesign]

Ok wait a minute please..

[igordesign]

http://www.igorvfx.com/forum/vray/color_map.jpg

Color mapping settings vlado

[Zdravko.Keremidchiev]

The Color mapping settings looks fine.
Did you try to increase the Light subdivisions or decrease the Adaptive Threshold?

[joconnell]

If you've got a hdri being used, you'll get cleaner results by loading it into a domelight rather than using the environment tab. With your lights, the 32 subdivs are getting divided by your 25 max aa samples, so 32 light subdivs divided by your 25 max aa leaves you with 1.28 light samples for each aa sample - it's not a lot. When you're choosing your light subdivs, try to use multiples of your max aa value. If you have 25 max aa, 25 light samples means 1 light sample for each aa sample, 50 light samples means 2 light samples for every aa sample, 75 means three and so on. I'd try using the hdri in a domelight and depending on how detailed the hdri is and much brightness range there is, start around 100 - 150 subdivs.

[Joelaff]

At least in Max I would check the cutoff value for the VRayMtl in the options. Perhaps it is too high? (Does Maya have that?)

And as suggested above I would try a lower threshold and double the GI subdivs as a test)

[igordesign]

Thank you friends, I will do what you guys suggested and then post the results here.