CGTalk - Updated to 3.1, Exported OBJ is now broken in pieces

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reformidatio

02-11-2008, 10:28 PM

I just updated by Zbrush to 3.1, didn't know about the normal maps feature. But I am getting beated up by the thing. I own the Digital Tutors Introduction to Zbrush 3, and I learned all the basics...

My problem is this: My normal maps are generating files that look great and perfect, but when I apply to my mesh inside maya and render with mental ray (as displacement etc), the final image shows the mesh with hard edges... as if I wanted to "show" the wireframe.

It shows the same thing as ZBrush shows a low poly mesh, with hard quads.

I managed to fix this my increasing my geometry to level 4, and generating a Normal map using level 3. It almost fixed, I think I can go up to level 7 and fix all... But I am thinking.. Maybe there is an easy way to fix this?

DrewShelton

02-13-2008, 12:36 AM

It's my understanding that you look for minimal distortion in SubD levels, viewing
the mesh's silhouette. If there's not alotta difference between, say level 3 and
level 6, delete all lower @ level 3, generate the normal map @ level 6.

Also, in Maya, is you mesh coming back in pieces? Must be a maya import option...
Also, to try to get rid of the faceted edges, try smoothing normals...Can't think of
the exact path on the top of my head. It is in the polygon/mesh menu set though.
Look it up under Help>find...

Hope I could help?
~ Drew

hakanpersson

02-13-2008, 10:38 AM

Post a screen pls. But I think you should go with Drew's advice and smooth the normals. ZBrush samples the normals as if the lowpoly would have smooth edges (and the mesh you import in maya have hard edges by default).

reformidatio

02-13-2008, 11:05 PM

Thanks for the help. :)

I will upload an image soon with more details.

"DT - Intro do Zbrush" tells the student to generate a Normal map based on the mesh lowest geometry... Is this correct? Should I always do on the lowest, or on the Highest possible?

CKPinson

02-14-2008, 10:13 PM

I did a dry run on ZBrush 3.1, since I just updated as well, and I got the same issues- I had a basic guy modeled (5k poly) and subd it up to level 5, messed around with the sculpting features then created a Normal Map- one smoothed and one not- in Maya 8.5 the one smoothed didn't have any ugly UV borders but did however appear washed out (the sculpting I did was smoothed and not as sharp). on the other one I had a nice detail of my scuplting but hideous borders at my UV edges.

reformidatio

02-17-2008, 10:58 PM

I think I found the solution, after re-watching the tutorial, I see they don't tell us - students - to use the lowest possible, but the geometry level used in maya (being the one you exported to maya). That should be the geometry level used to render the normal map.

I also managed to fix some of the strong details by incresing the samples to 3 (zbrush z-mapper samples).

thanks.

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