UV's UV's UV's

[moonlitmaverick]

Hi, I am relatively new to ZBrush. I have been interested to know more about UV mapping and UV’S in ZBrush.My questions however are of a very rudimentary nature.I wish to keep this thread about simple and elementary things regarding mapping and UV’s for absolute beginners like me.

1. What does UV stand for?

2. Is UV mapping used to wrap a texture map around an existing model, or are UV’s used as flattened references to be used for creating textures in 2d painting software? Or are they used in both instances? How does one handle UV’s in ZBrush?

3. I am attaching a reference image ( a creature from " The Witcher "). It is a beautiful example of a character evolved from a concept sketch into a fully textured 3d model (I would appreciate it if you could share
   examples of a similar concept development, modeling and texturing process ). My question is this:

IF I have a model created in ZBrush, how do I create a 2d texture map for it in Photoshop? How do I export the flattened UV’s from ZBrush such that I get a decent reference to paint on in photoshop.The UV’s sent to photoshop should look like a dragon( eg: ref image ),as that would make painting textures on them easier.

4. What is a 32 bit displacement map? And what is 16 bit?I have a rough idea what displacement maps do, that is, deform geometry along surface normals, but what is 32 bit? And how are displacement maps created in ZBrush or photoshop.

5. Can these displacement maps be created in Photoshop by exporting UV’s as references from ZBrush?

I will really appreciate it if some of our experienced members in ZBC could answer these basic questions. If there are aswers then I am sure there will
be more questions. Till next time ,keep ZBrushing

Attachments

[aurick]

To learn more about UV mapping, see here: http://209.132.96.165/zbc/showthread.php?t=8558

[system]

And to answer your specific questions:

1. It doesnt stand for anything. The U and V in there refer to the 2 directions of a UV map, ie horizontal and vertical. A better term for it would be something like ‘texture/polygon map’ but UV is the commonly used one.

2. Its the same thing in both cases. UVs are basically a guide that indicate what part of a texture goes where on a mesh. So you can either start with a texture and create a guide to stick the texture where its needed on the mesh or you can start with the guide and create a texture around it.

3.1 The ref image, while a good model and concept, would make a very poor UV map. Like i said, UVs are nothing more then texture/polygon guides, so they need to follow certain rules before they can be used as such. The most important of these rules is that non symmetrical areas of a mesh should never ever overlap. Or in other words, every unique part of a mesh should have its own unique UVs on the UV map. If you do not do this, then the computer (and human) can no longer texture the areas of the mesh that are being hidden/overlapped by each other.

eg in the ref image, if you were to use it as a UV map, how would you apply a texture to the part of the dragon’s body that is being hidden behind the wing ? Or the side of the wing that is hidden from view ? Ideally you would separate both sides of the wing and lay it flat in its own little area of the map so you could texture it properly.

Note that for symmetrical areas you can use overlaps, like say 2 halves of a face being mapped to one area. But in that case you would get the same (mirrored) texture on both sides.

3.2 About ZB, unfortunately ZB makes a very poor UV tool. It only has its auto mapping (which cannot be painted on in photoshop) and its simple projections (which cause overlaps and stretching) A better way is to export the base level of your mesh into a mdoeller or UV app and do the mapping there. Then you can import the file back into the lowest level to get the UV mapping. Finally you can export thr UV map as a texture file, either from the modeller or ZB and paint on it in Photoshop.

4. the ‘bit’ in this case refers to how many levels of precision you can have in the map. eg if you had a 1 bit displacement map, you could only have full (1) displacement or no (0) displacement. For a 2 bit map you could have 4 levels of displacement, for 3 bits, 8 and so on. So the main advantage of a 32 bit map is that you can capture finer and more detailed bits of your mesh then with a 16 bit one.

5. Short answer yes, do a texture–>UV check and export the image thus created. But to actually get a image of the UVs that you could paint on in Photoshop, you need to do the UVs first in a better tool then ZB.

[moonlitmaverick]

Thanks Aurick for pointing me to the pdf, it appears to be a promising guide.

Thanks Ghonma for taking the time to answer all my questions. I am going through the information you provided and will post more questions if I need more clarity on the subject.

[roger_01]

I have a question about uv’s in maya to zbrush. I have read some documentation of proper uv layout in 3d apps is vital before importing into zbrush.

Question: What does it mean to have a 0 to 1 ratio for uv mapping in 3d apps (before importing to zbrush)? :lol:

Thanks