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View Full Version : questions about guv and auv tiles, and importing uv maps from other programs


Womball
04-19-2006, 03:22 AM
I'm curious about how zbrush's uv tiles work. They seem to create UV maps that you really couldn't easily edit in other programs. Unless zapplink is used for this. When I make a UV map in blender, I try to maintain intergity of form and and hidden seam placement. However painting textures this way is a pain since you have to go back and forth between image manipulation program and the cg program. This is what I'm intrested in zbrush for besides making bump maps. Is my method of creating planned out UV"s archaic with zbrush? Does zapplink or zmapper take care of these issues.

BTw an examples of my UV layouts are in my journey entry.

Womball
04-20-2006, 04:42 PM
Hmmm maybe I should rephrase this. what exactly does zapplink do, and can guv tiles be used in any software? Are manually unwrapped and tested uv's better than guv or auto uvs in zbrush? It seems like their would be tons of seams.

TVeyes
04-20-2006, 11:16 PM
GUV and AUV tile mapping are as you said not suited for painting using a regular 2D program such as Photoshop. In ZBrush you usually use Projection Master to 'drop' your 3D model, then paint with any 2D, 2.5D or 3D tools in ZBrush and 'Pick' up with Projection Master to transfer the modifications to the UV map. You never see the disjointed nature of GUV and AUV mapping but paint straight on the 'dropped' model. The Zaaplink plugin extends this workflow by allowing you to modify the 'dropped' model in a .psd capable program such as Photoshop and transfer those changes back to ZBrush before Projection Master 'Picks' up the model. In either case you never work on the disjointed nature of GUV and AUV maps.

It is hard to say why you should or should not use GUV/AUV mapping, it all depends on what your project dictates.

If you are doing a still picture, GUV/AUV mapping makes sense as you save time unfolding UVs the normal way, which can also result in inferior mapping. As a 1 button press GUV/AUV mapping is much better than a quickly unfolded UV map, IMO. But due to the many disjointed UV edges it also has some drawbacks. All depending on your render application some texture filtering functions can result in seams along the UVs in the final render. All UV maps can suffer from that which is why people hide UV seams where the camera does not go.

So if you want to know if GUV/AUV mapping is for you do some quick renders to test out what you need to adjust and what you need to omit in your render engine.

If you are using the ZBrush demo version you can test the AUV mapping using the model and texture from >> This << (http://www.zbrushcentral.com/zbc/showthread.php?t=20244) thread.

Haker
04-22-2006, 04:50 AM
ZBrush 2 works great with Blender. I personally use the GUV tiles without problems, as long as you export .obj . The only problem is the image placement on the UV display, this is easily fixed, just select all of the vertixes (on the UV layout window in blender) and mirror it on the Y axis. Or else just fiddle around with the Zbrush export options.

I got straight from Blender to Zbrush, then back to Blender, not other programs required.

Womball
04-24-2006, 04:17 AM
Do you use displacement or normal maps? Blender doesn't support micropolydisplacement either, so I'm stuck with high sub-d levels. How do you get zbrush to recognize the .obj's uv data? I carefully laid out uv's ahead of time, its pretty easy using the CVS builds.

Womball
04-24-2006, 09:13 AM
I figured out how to get my UV's to work. They are a texture sheet layout btw. However they didn't create individual poly groups for each island. It would be nice if the arms were different colored than the chest. Make it easier to select too I think.

Haker
04-25-2006, 07:25 PM
Assign seperate groups to the arm and chest areas, the .obj stores that imformation. Also the displacement maps can be exported in an alpha map, Blender supports it as long as you have your UV's aligned, althought depending on how high you subsurface your model in blender there might be a loss of detail.

benclark
04-26-2006, 11:42 PM
From what I've seen you can auto assign your UVs in Zbrush if you are using displacement maps. Thats what the guy does on the Zbrush pipeline dvd from Gnomon

I tried doing this for Normal Mapping and the results were horrible

I just lay the UVs out - that way you have total control over it

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