uv fundamental

imk

Hi, i wanted to know more about the fundamentals of uv unwrapping. What is a good uv, does the uv has to be all straight quads?

I tried drawing lines on a character but it came out jagged and distorted. I believe that it is because of my uv.

Please share some of your knowledge,

thanks

Deadly Nightshade

Good UV's are when the shells give proper texel density to the model (high TD on things that are very visible, close up to the camera and so on and low TD on things that are rarely visible - such as the underside of a car).

Good UV's utilize all the available space on the texture map.

Good UV's have proper spacing between them (ie: you don't get texture bleeding from one shell to another when the texture is mipmapped)

Good UV's does not add unnecessary smoothing groups to the model (every individual shell is a smoothing group. Hard edges = edge split = double vertices)).

Good UV's does not cause ambient occlusion and normal map artifacts when baking AO and normals.

And on lowpoly/pixel graphics: good UV's are aligned to the horizontal or vertical axis (because painting diagonally gives you anti-aliasing). This is why lines get "jagged" and "distorted" when you work on say, a lowpoly character or object.

Eric Chadwick

Good advice. Also more info in the links here. http://wiki.polycount.com/TextureCoordinates

imk

thanks, i read a few tutorials. Then it struck me that we should unwrap objects as if you are unwrapping it in real life. Etc. the way the shirt is sew together

Am i right?

Eric Chadwick

Yeah, generally shirt seams are placed in good locations, because the fabric starts out flat, much like your texture does.

Not always though. Sometimes you'll want to shift the seams around to fit details in your mesh. Like for example you might have a bandolier running across a shoulder, so your UV split there would take that into account, and bend around it a bit.

Generally, I try to put UV seams into creases or behind raised details or under arms... out of the way places where errors won't be noticed as much.