CGTalk - Stretching and bumpiness

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kyphur

08-24-2002, 09:43 PM

Hey, I'm having some difficulties with this:

Molly's index (http://www.kyphurland.com/img/full/maya/3d/jotelle/082102/)

This is my first project where I've actually textured something really hardcore. The main thing I'm having trouble with is stretching on her lips, neck and nose.

These are the steps and software I'm using:

Maya 4.0.2
Selecting my object and then going into EDIT POLYGONS> TEXTURING> SPHERICAL MAPPING

I select that then go into UV TEXTURE EDITOR where I cut my nose and ears off the model's UV's. Then I unrwap them and re-attach them to the main surface that I have. Take a UV Snapshot and paint it up in photoshop. When I bring it back in there's some stretching on the lips, and around the ears and down the neck and the nose seems to scrunch up the texture. Is there a way to keep it from doing this or do I have to become adaptive and try to fix it in Photoshop manually? Does the distance between the UV's dictate the amount of stretching/crunching? Does RELAX UV's in the TEXTURE EDITOR help with this or is it just a simple tool for helping you figure out where your ends are?

Any help would be greatly appreciated.

Kyph

PS> Btw, The maps for bump and spec are updated but I haven't posted them to my site. The bump now is more along the lines of what I want but when I get right up on it looks like acne. I want to be able to afford close ups and long shots without sacrificing the quality. Do you have any suggestions?

PPS> This is a stylized peice and I'm really beginning to think about not going for photorealistic skin in the sense of true skin but something else. I don't want to add lines into the texture because I'm afraid that it'll seem like wrinkles or age marks when this girl is supposed to be young.

leigh

08-26-2002, 08:40 AM

Hey Kyphur, I was about to email you back but I see you've posted here, so I thought I'd reply here so that other people can (hopefully) find this problem (and hopefully solution) of some help too :)

Hmmm... looking at your UV unwrap, I must say that you have a neat, clean unwrap so there are no worries there by the look of things...
In other words, you don't have to worry about the relax UVs function here.

What is causing the stretching however, is that when any object gets unwrapped, a certain amount of stretching is going to happen, no matter what.

When I have unwrapped an object, I usually take quite a while to sit down and edit the UVs so that the proportions of the UVs are more or less the same as the original polys.

I've said it before, and I'll say it again - no UV unwrap is ready to be used for painting straight off - they ALWAYS require a certain degree of editing.

However, the good news is that the stretching shouldn't be too hard to fix in your case.

Now, I'm not sure how you would do this in Maya - what you need to do is work in your UV viewport. The same way as you would when you are editing the points.

This is how I set it up - I change my display to 2 viewports - one perspective, the other UV. Now, make sure that your perspective viewport is displaying all you textures in OpenGL - basically you need to be able to see your colour map.
Now, with the model loaded, with the colour map visible on the model, just move the points in the UV viewport around, and you should see the colour map on the model adjust. So basically all you need to do is tweak the points around the areas where there is stretching, and eliminate the problem :D

The cool thing about doing is this way is that you don't need to redo your image maps - you rather tweak the model to fit the maps, instead of the other way around ;)

Tumerboy

08-26-2002, 03:29 PM

Leigh, I think you're on the right track, but I disagree with a couple of things.

Yes there will always be stretching, and no, no UV is ready to go after just doing a cyl map.

But I do think that kyphur will need to repaint some of the image.

The problems with stretching, is what Leigh said, the proportions of the lips in the UVs doesn't resemble the proportion of the lips in the model.
So you need to bring up the UV editor, and the front view, and try to make the UV lips look more like the front view of the model's lips.

Now, I don't believe you can simply tweak the UVs and keep the same map. I think that if you make the lips (or any other areas that are stretching) look like the respective areas on the model, then your new UV lips will be much larger than the image you've got. . . so fill them back in. But that should fix your stretching.

Keep in mind that this will stsill require a decent amount of tweaking, so once you think you have your UVs right, don't start in depth painting just yet. . . try out a checkerboard image or something with a regular pattern that you can tell is stretching when you apply it to the model.

Hope that helps.

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