UV Texture Map Question for Character

kmyung

Hello there, I am creating my first game character, so forgive me if this is a bit of an obvious question but I couldn't find the right resources. 
I am done with re-topology and am onto UV's, but I can't fit all the UV's to my UV square. Do I simply reduce the UV shells together as a whole to fit or selectively reduce UV shells that are not so important in the model?

Also, as I understand it- all UV shells need about the same texture size except the head which should be a bigger UV shell? Is this correct? 

One last question that came to mind. Does UV orientation matter for the shells? I kept them all vertical or horizontal but can they be placed at angles?
Thank you as always.

Alex_J

Orientation does not matter, but in some cases a thoughtful layout can make for easier texturing -- for instance with hair cards all facing the same direction.

About scale -- you are on the right track. I think if you spend some time studying the wiki, you'll be able to answer these questions yourself.

Do you know about stretching and pinching? Having your UV shells squared like that may help with organized packing, but I think you will find a lot of deformation in places you might not want it. There is a helpful tool in Maya to give you a visual overlay to see if your UV shells will be stretching or pinching in certain areas. It is the third icon in the upper tool bar, but you'll need to read the UV editor documentation to understand how to use it. You can use the unfold and optimize tools to help you overcome stretching/pinching problems. Don't try to understand all of this if it is unfamiliar, just use the keywords to search and learn more from comprehensive tutorials/documentation.

In short, there are no rules about the scale. But you have to understand texel density so that you can get the results you want from your model. If you make the face very large, it receives greater texel density, while other areas would have to receive less. Some parts of the mesh may be totally hidden, and so you might scale them very small to tuck away in a corner, and some parts may be able to receive the same texture, but mirrored. 

Getting a little more complicated, you may decide that you want a lot of texel density on many parts of the model -- more than you could achieve if it was all packed into a single UV space. In that case, part of your model goes into one UV layout, and other parts go into another. The theory is simple enough, but depending on what programs you are using, you will need to understand how to separate objects by material/UV set. None of this is very hard to do, but it's a bit of a headache to figure out in the beginning, and that's why I recommend studying the wiki, perhaps watching a few tutorials, and then when you go forward with your own project, do so with patience and the thought in mind that you are going to have to do things over, and probably several times before you get a good result.

Until you understand what is happening on a fundamental level, you'll be stuck following advice and instruction like, "Click this, click that, voila." But it's hard to find instruction for exactly the programs and workflow you will be using, so that is why it's key to try and wrap your mind around what you are actually telling the computer to do, and what it is doing.

As a rule, I always leave my 3d app open while I am texturing in Substance Painter. All the time I will be painting away when I realize I could be getting more performance from my UV layout, so then I can just hop over into Maya, adjust it, and then reupload in Painter and continue on. It took me a lot of headache and frustration before I realized how easily I can use these programs in such a way. I used to have this incorrect idea that once I did a step, that was that and there was no going back. So I encourage you to take pleeeeenty of time really getting comfortable with UV layout so that it's not an unnecessary thorn in your side.

kmyung

Wow. Thank you so much for the lengthy response you are a fountain of knowledge.

I am aware of textel density and stretching/pinching, but I am not completely comfortable with the ideas so I will look more into them.

There has been so much to take in with the process of creating a character, but I am learning so much through trial and error especially when people like you help me out.

I love the idea of having Maya open with Substance. I actually did quite a bit of the same where I had topogun open with Maya and fixed some topology that wasn't working well with UV seams. 

Thank you BIGTIMEMASTER. 

Alex_J

Don't expect to get it all in one go. Once you get into your texturing, that is where you will start seeing how mistakes in your UV layout effect the process. For instance, if you are trying to get little pore's on the nose, you may find that they are appearing kind of blurry, while if you use the same brush on the cheeks, they are very crisp. So then you go back and look at your UV's and you can see that there is some stretching in that area, and so you know to google "facial UV layouts" and you can browse around and see what other people are doing. 

Ideally you get it right the first time, but you can't expect that until you've learned all the mistakes that can be made.