View Full Version : SubD MR displacement going crazy!!!

05 May 2007, 12:27 PM
I've got this weird problem and I can't figure out what might be the reason. Has anyone come accross something like that?

Ok, I've got a character that I modeled in poly, UV mapped it and started to make textures.
I want to make some displacement maps as well. Converted it to subdivision, went to the Approximation editor, added Displacement Tesselation and when I rendered it I got a weird mess (see the images below). I tried to figure out what might be the problem, but the only thing a found, is that if I collapse hierarchy on the subdivision surface, my UVs go crazy. So, any ideas?


(here are some snapshots of the polygon surface)

05 May 2007, 12:31 PM
and here are the SubDivision shapshots

05 May 2007, 02:24 PM
I don't think that has to do with the approximation editor
I seen that problem before when people trasfer OBJ ffrom Maya to other scuplting application such as mudbox or Zbrush
you will have to look carfuly in your pipleline to catch the problem

05 May 2007, 03:45 PM
Topology of Your model is incorrect.
You CAN'T have faces with more than 4 edges, so You better poke them or manually subdivide them to be at least quads.
Other thing, subD's aprox makes problems with triangles by default, so under assigned mr aprox node You should find 'Mesh Conversion' tab, and change it from 'None' to 'Quads To Triangles'.
EDIT: Now I saw Your poly mesh and indeed topology LOOKS correct. Check out that You don't have nonmanifold geometry, or that some vertices are not properly merged, so that some faces that APPEAR to be quads or triangles haven't got more sides in fact.

05 May 2007, 07:38 PM
I already thought that the topology might be a problem and have fixed that in another scene - I had only quads and triangles, but the result was the same. I will try the conversion though. Thanks

05 May 2007, 10:18 PM
Just stick with polys

06 June 2007, 05:55 AM
Just stick with polys


No reason to physically convert the mesh to SubD because to be frank, Maya's SubD's suck. You can convert the poly mesh to SubD at rendertime with mental ray's subdivision approximation node attached to the mesh.

06 June 2007, 09:01 AM
Thanks all. Polys work good. Guess I am going to stick with them.

06 June 2007, 08:33 PM
Just a tip..

You have at least 25% of your UV assigned to nothing. While spacing it out nicely is pleasing to the eye, you should try very hard to get your main mesh shells to take as much room as they possibly can, while also having your smaller parts taking up a relative amount so the texture doesn't look less refined in those areas.

The benefit of this is more clarity or also the option to reduce the texture size due to the increased UV space gained. You cannot change it now, but your next project I recommend you scale those UV shells up :)

Example :

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06 June 2007, 08:33 PM
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