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Normal Maps in Maya from Zbrush 3.2 (OSX)

ZBrush Usage Questions
#1

Hello, i am quite new at Zbrush, so I hope this is a problem with my process rather than a problem in ZBrush on the Mac.

I’m getting hard edges in the normal map (seen and sometimes unseen in the image file) where the geometry edges are. When I bring the model back into Maya, and look through the viewport or render an image, it becomes quite apparent. The problem is showing up only in parts of the geometry and not the entire geometry. I’ve tried different configurations and it always seems that the normal maps display generated in ZBrush 3.2 (mac) produce undesirable results to some degree.

Here is my process:

  1. In Maya 2008 (mac)
  2. Select my geometry and hit GoZ
  3. Set morph target for my geometry
  4. divide some and then detail
  5. Go to the lowest geometry level
  6. Hit Switch for morph target
  7. Generate Normal Map
  8. Click GoZ to go back into Maya
  9. In maya, I smooth normals to remove facestting
  10. View as high quality render to see normal map in view port or render in mental ray

Changing the UV’s seems to have an effect on where these artificats show up. Attached are several files that show what i’m talking about. In this case, you can see the issue within the normal map, but other times, its not apparent. Has anyone had a similar issue and are there tips to keep this from showing up?

Is this an issue with my process or an issue with the software in general? I know 3.1 for the Mac had issues with normal maps but im not sure if this is a continuing problem.

Thanks!

seam.jpg

Attachments

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seam3.jpg

rightSleeve4_geo_NM.jpg
rightSleeve4_geo_NM.jpg2048×2048 107 KB

#2

I suspect that some of your UV’s are becoming unwelded somewhow. I don’t know why, but it’s probably a setting somewhere in Maya, or possibly something that’s happening as you lay the UV’s out.

#3

I have found that this is actually a Zbrush issue in 3.1 and 3.12(a,b), and 3.2.
Zbrush is unwelding UVs when you export back to maya. I have exported objs to C4d and max and back with the same settings from maya and everything is fine, so its not a maya side issue.

I have found a 3-step fix for it though:

http://www.andrewklein.net/ai/zbrushdemo/fixuvs.jpg

#4

Hey, it worked!! Wow thats dumb that it has to be done that way, but at least theres a work around. Thank you slorpthegillman! With GoZ in 3.2, however, it not setup to export the Enable Mrg. Do you think theres a way to set that up for GoZ or customize GoZ export?

#5

Aurick,

BTW, the fix that worked here for sethfair..... it doesn't work with GoZ. Any mesh sent back and forth with GoZ will break apart at UV shells.
#6

I’ve tested it as well and it always seems to break the uv’s with GoZ but not when i do an export. So the initial suspicion from aurick that the uv’s were being unweleded was correct. Its too bad however that its GoZ that is doing it. This makes GoZ essentially unusable since the main purpose I see is to setup these texure network in the hypershader. Is everyone having this problem or is it just for the Mac? Is there a work around for GoZ?