dark polygons problem with FBX import

[Juraj]

Hi,

I have strange problem with some polygons.

When I import FBX model sculpted in Mudbox, I get theese dark polygons in rendered image.

However it looks fine in viewport.

I have tried different FBX import options, or SOPs like clean, fuse, facet... Nothing helped.

Normals are looking fine.

 

 

Any ideas how to fix it?

Thanks

[Juraj]

I tried to import this model into Blender, where I have same issue.

 

But subdividing mesh with Catmull-Clark algorithm fixed it. Is there another way how to fix it? There are too many polygons now .

[Guest tar]

they should be self-shadows and are apparent as you most likely have low polys and smooth normals - they can be removed by:

 

increase your bias in Mantra/Properties/Shading

 

or

 

Check Render Polygons As Subdivision (Mantra) on your geometry node/ Render tab

 

or

 

check Backface Removal on your geometry node / Render /Geometry tab

 

Find out more:

 

http://odforce.net/wiki/doku.php?id=raybias&s[]=bias

 

http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=31385

[Juraj]

Thank you, your solutions fixed it.

I'd never figure it out by myself.

 

I also tried to import it into Maya and render with Maxwell and Mental Ray. Interesting that Mental rendered it fine by default.

Edited May 18, 2014 by seals77

[Guest tar]

is Mental Ray using shadows there?

[Juraj]

No, it wasn't. Now when I turn shadows on polygons go mad.

Wondering how to fix it in other renderers. Can it be done on model level, or just in renderer settings?

[Guest tar]

the artefact is created by the shadow. the shadow is created by at shader/render time so it has to be dealt with then.

 

Edit: woudl it be possible to post a screen shot of the mental ray with shadows, thanks! It would be good to see it to compare.

Edited May 18, 2014 by tar

[Juraj]

rendered in Mental Ray