Vray smudges on some surfaces

[fernando-1]

I can't figure out why some surfaces are rendering with smudges in Vray (3dmax) see screenshot below.

Please suggest a reason why. Thanks

 

 

 

Edited June 5, 2014 by fernando-1

[Zdravko Barisic]

Its a 99% overlaping faces.

So you may have 2 face one over other in one single object, or just 2 object, one over another, but placed at the very same position.

This ussually happens when importing from ArchiCAD or Revit, sometimes...

[fernando-1]

Zdravko, thanks that's what I thought myself too so I copied the surface and still renders the same smudges on the new surface.

[Ismael]

http://www.cg-blog.com/index.php/2012/10/22/splotches-vray.htm

 

http://forums.cgarchitect.com/71909-v-ray-gi-hdri-splotches-blotches-spots.html

[Francisco Penaloza]

If it is a geometry that you imported from other 3D or CAD software, check for double geometry fist, then check normal and smooth groups, sometimes un-weld vertex create strange behaviors like this ones.

an easy way to check if it is GI or geometry problem is put a soft light in front of that area, is you have geometry problems it will still render like that, if it shows clean then you need to fix your GI, interpolation or number of sample, radios all that mabo jambo

[fernando-1]

Yes thanks it was something to do with the geometry... I re modeled the same shape and the smudges went away.