ZBrush to Maya baked surface texture gone wonky

Hi -
Can someone tell me what's going on here? It's a poly torso model built and imported from Zbrush - the baked surface texture seems to be split into sections with strong dividing lines of different contrast across the borders.
Ta!

 

I know that there was an issue with normal maps in zBrush 3. It was solved with Version 3.1. Maybe an update can help.

 

Looks like it's using zbrush's adaptive tiles instead of a UV map. Go down to the lowest subdiv level and reimport the obj with the UV map. Click "Check UV" in the Tools/Texture panel to confirm there's a valid UV, then regenerate your map.

 

Hi - that makes sense polytropoi, but bear with me, I'm still a nubie. I am stuck on ZBrush2 atm.
So I open the model (keeping at low rez) and go to tools and do a "UV Check" and then "Normal Map/Create Normal Map"? (with the various options off?). Tried this ad not working. Various combinations just produce a useless map - any specifics you can give me?

Thanks!

 

Are you sure your geometry has a UV map? The UV Check button should create a texture with UV boundaries visible. If it doesn't, no UV on your model.

Zbrush forums and docs are pretty good resources. Also realize that Unity can convert any greyscale picture to a normal map, just toggle the Create Bumpmap selector in the Import Settings panel:
Therefore, all you really need to make is a displacement map, and let Unity convert it into a normal map. That's what I do. You can even desaturate your colored texture, although that's rarely convincing.

Zbrush is very sexy, but it's a good idea to get a handle on UV mapping and texturing in Blender first, if you're just getting started.

Good luck, and welcome to Unity!

 

This is something that really bugs me about Unity - the terms for Normal, Bump and Parallax maps are all rolled together under the term "Bump"

Correct me if I'm wrong here but...

A bump map is a gray scale that only has height info - no directional information

A normal map is an RGB which stores the normal of the baked polygon normal into a pixel (really a texel once UV mapped) and has no height info (XYZ channels to RGB channels)

AND

A Parallax Map is an RGBA where the normal is stored in the RGB channels and the height is stored in the gray scale alpha channel

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Now I ask how can Unity generate a normal map from the diffused textures gray scale?

I understand RGB to Gray Scale for a FAKE (bump) height map.

But have no clue how diffused color OR gray scale can FAKE a normal map. Where does the faked baked normal come from?

Cheers,