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normal map and color map don't match

ZBrush Usage Questions
#1

Hello,

First, I apologize if this has been covered before. I did do a search and nothing seemed to match the problem I am having (actually one post did, but there was no resolution). Please feel free to direct me to the appropriate place if I missed any solutions!

The problem:

  1. I have a normal map generated from a high poly zbrush model (using Zmapper and the preset for high quality for Maya).

  2. I apply the normal map in Maya 7 with no problems.

  3. I then polypaint on the high poly model in Zbrush.

  4. I create a texture from the polypainting. It looks fine on the high poly model in Zbrush.

  5. When I apply the color map in Maya the color map does not match up to the bumps defined by the normal map. It’s close, but it is off by a bit in certain areas. It’s as if Zbrush, when creating the normal map, smooth subdivides the UV and thus distorts it by just a bit.

Here is an image showing the problem:

Suggestions?

Cheers,
Paul

edit: I didn’t smooth the UVs when I subdivided the model

#2

Here is more information… if that helps. In ZBrush I applied the normal map that ZMapper created to the high poly object to see how the normal and the high poly matched up. You can see the mismatch:

It pretty much shows the same problem as the color mismatch in Maya. So the normal map generated from the high poly doesn’t match the high poly object (note that it does match in other places). Is there a way to fix this?

Cheers,
Paul

#3

I’ve never seen this, and I shouldn’t be helping you…damn CGtalk’er I think. GameArtisans myself.

Possible reasons for the mismatch could the UV’s, Bobo’s weren’t the best and should be redone (they’re not bad, just not perfect) Also, how dense is the mesh you’re working on, and what size diffuse and normal maps are you dumping out?

1k for a 1million mesh that is using 100% of the map, 2k for a 4million, and 4k for a 16million.

#4

Hey Goast666… thanks for trying to help out a fellow rival.

Yep, I reworked his UVs… no overlap, and where the problem occurs there is plenty of space. The mesh is subdivided 8 times… I think it’s just short of 7 million polys. I’m dumping out 2k maps - I can try bigger, but I don’t think that will solve it since the UV normal and cavity map don’t map to the high poly. But I’ll give it a try.

All the best, by the way, on the mini challenge!

#5

Yep, tried different resolutions. Same problem. Thanks for the suggestion though!

Cheers,
Paul

#6

Update: Ok, so I tried the other way of making a normal map (on the objects tool menu->Normal Map) instead of using ZMapper. That produces an ugly normal map - BUT, it fits the subdivided high poly exactly - the color matches the normal bump map. So there must be an option on ZMapper to make it fit and produce a nice normal map. Anyone?

Cheers,
Paul

#7

Here is a visual aid to the problem:

For Zmapper I’m using the config file called “Maya_TangentSpaceNode_BestQuality.zmp”. I’m playing with different settings under the Normal/Cavity Map/Projection/Expert Pass etc tabs, but there are just sooo many combinations and the documentation is pretty scarce…

Cheers,
Paul

#8

im having he same problem as you but on 3.5 .
i can do a bump map and that matches up with the texture fine, but the normals are allways squished or sightlig off to one side.
tried every thing redone the uv’s many a time including using the uv master in zbrush allways the same sort of result.
at a bit of a loss with this one;)

#9

I think my only solution was to increase the number of polygons in the model. That helped a bit.