UV Layers - How do they work?

(Ghost_Train) #1

Hello,

I’ve been doing searches like crazy to try and find answers, but can’t find anything
on how to make use of UV layers.

Does anyone know of any good tutorials on this? Or can you explain it briefly?

Also if I had a plane, unwrapped it and applied a UV texture to the whole thing,
how do I make use of another UV layer? is it at all similar to layers in Photoshop?
What if I loaded a second image with alpha channel…like a logo with transparent
background and wanted to lay that on top of the previous UV texture? How? Once
I load another image into the UV/Image Viewer to map it to my unwrapped model,
it completely overrides the previous image. I’ve messed around with adding
a new Material index (2 Mat 1, 2 Mat 2, etc…) and added more than one layer, but
with no effect. I know how to successfully unwrap and UV map an object, but
only with texture image.

:spin: Am I making sense or is this too wordy? <—Don’t answer that one.

This is the most I’ve been able to find on it:
http://www.blender.org/development/release-logs/blender-243/multiple-uv-s-and-vertex-colors/
…but it doesn’t really explain anything in a way I can understand. If anyone
can make a short step by step tutorial on how to use multiple layers, I would
hug them…more than once…but less than 5 times.

Please help.

P.S: For real though, no hugs.

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(denshidan) #2

This thread give some insight to how uv textures work

http://blenderartists.org/forum/showthread.php?t=120165

a more general into is
http://wiki.blender.org/index.php/Manual/Working_with_UV

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(harkyman) #3

It seems that you might misunderstand one of the basics:
“UV Layers” has nothing to do with actually layering imagery or colors as it does in Photoshop. “UV” refers to the set of coordinates that map a 2D image onto 3D geometry. So, when you hear people talk about “I UV mapped this model” what they mean is that they assigned UV coordinates to the model, and then used the regular material and texturing tools to assign an image map, and it was set to use those UV coordinates, as opposed to one of the other methods (orco, global, etc.).

The ability to create different “UV Layers” has little to nothing to do with how your textures will blend and work together to produce a final material. Adding additional UV layers is just creating new sets of UV coordinates, which may or may not be useful to you.

It seems from your post that you need to learn the texturing stack in the material editor. From there, you can use a number of different image textures, and set them all to use your UV coordinates.

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(PapaSmurf) #4

to add to what Harky said, you layer textures using texture channels, with each channel mapped to a UV Coordinate set (I agree UV Layer as a term is confusing). see wiki on Textures and channels.

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(CD38) #5

One use of the multiple UV maps is to remove seams in textures. Say your UV mapped texture has a mismatch where you had a seam in the arm. You would unwrap the arm with a second set of UV coordinates that has the seam in a different place. Now you bake the original texture to these new coordinates. The mismatch ends up not at the edges, but in the middle of the new image, where it’s easy to edit out in GIMP. This becomes your final, seamless texture. Someone wrote a nice tutorial on this a few months ago. I will try to find.

Edit: The tutorial author is Cire. It is published in Blenderart Magazine, issue 12 which you will find here.

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(Ghost_Train) #6

Awesome. I think I’m starting to get somewhere with all this now.
You guys rock. Thanks for sharing all this info. I don’t know why,
but I for some reason thought I could only at one image texture to
the stack. Maybe I just didn’t play around with it enough. I tried
doing some of the things mentioned here and I’m seeing results.

The only thing I need to figure out give each texture layer it’s own
UV coordinance. I got them both to show up, but They both appear
in the same places.

I just need to go read up on the links you posted here.

Thanks again.

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