Texturing a polygonal head model

The following describes how I setup the UV's for my model in order to paint the textures.

Step 1: make a duplicate of your model. This is important so you don't mess up any of your original model. Later you can transfer the UV's from this duplicate back onto your original.

Step 2: On the duplicate, select the areas that are the most complex (ie. nose, ears, eye area, lips). (you probably will want to do this step one area at a time).

Step 3: now you'll want to average your selected vertices. You can get to this command through the Polygons>Average Vertices>options menu.

Set the Iteration value to whichever you feel is appropriate. I set mine between 10 and 50 and applied it a couple times. Repeat this step for all of your complex areas on your model. The reason for averaging the vertices is to make the more complex areas of your model less complex, so after you apply the Cylindrical projection, you won't get so many (if any) overlayed UV's, which will cause problems for your mapping.

When you're finished with that, your duplicate should look something like the images on the right. As you can see, all the more complex areas of my model are now less complex and more planar, which should make a better cylindrical projection and UV layout.

Step 4: Now you're ready to map the UV's for your model. Select your duplicate model and go to the Edit Polygons>Textures>Cylindrical Mapping>options menu. I just used the Smart Fit option which fits the projection automatically around your selection. You're welcome to play around with the different options, but for this instance, these are the settings I used.

Step 5: In the attribute editor for the cylindrical projection, you'll find the following options (right image). Make sure you set the Rotate Z value to 0.1. Maya has this weird habit of messing up the UV's of the cylindrical projection, and this seems to fix the problem. These are the settings I used.

Step 6: I also noticed that the UV's for the top of the head and the UV's for the neck area were garbled
from the Cylindrical projection, so I selected the poly's on the top of the head, and did a planar projection for those, and selected the poly's around the neck and did a second Cylindrical projection for those.

So I ended up with 3 UV shells in the UV Texture Editor, which I'll need to sew together to get one unwrapped UV shell





Step 7: Now it's time to use the Move and Sew command. Select the edges of your neck shell (which automatically selects the connected edges on the other shell) and use the Move and Sew command (Edit Polygons>Textures>Move and Sew)(this command can also be accessed from the UV Texture Editor's Polygon menu). Do the same with the top of the head's shell.

You'll see that all 3 shells are now joined. But the UV's are pretty bunched up where you've sewn them together. This is a job for the Relax UV's command (next step).

Step 8: You can use the Relax UV's command to space out selected UV's into a more neat layout. Just select the UV's in the problem area and use the relax UV's command.

NOTE: don't do this too much or you'll probably get stretching in the textures where you've relaxed the UV's too much!

Step 9: When you're finished and happy with your unwrapped UV's, select the entire shell, and go to the Polygons>Layout UV's>options command in the UV Texture Editor. Change the settings to what I have in the picture on the right.

You want the Separate option off so that Maya lays out the UV's in 1 piece. Then the Layout option you want to select "Into Square" so that maya fits your selected UV's into one square unit. The Scale option you want to select Uniform so that Maya scales your selected UV shell uniformly to fit inside a 1 unit square.

Here is a screen shot of my finished UV's. Not perfect, but you get the idea...

Step 10: After your UV shell is layed out in a 1 unit square, select the model and go to the Polygons>UV Snapshot command in the UV Texture Editor. Change the path/filename to whatever you choose, set the XY size of the texture to be created, and the Color Value for the UV's, and image format. After you select OK, an image file is created with your UV's and an alpha channel in the image format you selected. You can now take that image into Photoshop (or image editing software of choice) and start to paint your texture. (next step).

Step 7: Now you need to transfer the UV's from your duplicate back onto your original model. There are a couple different ways you can do this, and all work just as well (as far as I can tell). One way is to use the Polygons>Transfer>Options command and select UV Sets only. Another way is to select each face and choose the Edit Polygons>Clipboard Actions>Copy>Options (can also be found in the UV Texture Editor under Polygons>CopyUV/PasteUV) and select the UV attribute only, and do that for every face of the duplicate and paste it onto the matching face from the original. I wrote a quick script that does this automated, and you can grab it from here:

// ckUVCopy.mel
// Copyright � 2001 Secret Level Inc.
// Author: Chris Kniffen (kniffen@secretlevel.com)
// Created on: November 4, 2001
// Performs the copy/paste UV command on all faces
// in the objects. Objects must have exact facet indices
// for this script to work.
// Destructions:
// Select the object with the modified UV's first, then
// shift-select the original object, and run the script.
global proc ckUVCopy()
string $selObjs[]=`ls -sl`;
if (`size($selObjs)` != 2)
error "Must ONLY have 2 objects selected.\n";
int $modObjFacets[]=`polyEvaluate -f $selObjs[0]`;
int $origObjFacets[]=`polyEvaluate -f $selObjs[1]`;
if ($modObjFacets[0] != $origObjFacets[0])
error "Selected objects topologies do not match.\n";
waitCursor -state on;
for ($i=0; $i<($modObjFacets[0]+1); $i++)
polyClipboard -copy -uv ($selObjs[0] + ".f[" + $i + "]");
polyClipboard -paste -uv ($selObjs[1] + ".f[" + $i + "]");
waitCursor -state off;
print "UV Copy Finished.\n";

Step 8: Here are my textures in progress from Photoshop. I'm still working on them, but they look ok for now. No specular map yet either, but on the right you can see my colour and bump passes with the UV's layed on top.

And here's a render of my old guy model with the textures applied and some lighting.

So, that's pretty much the dumbed down version of texturing in Maya.

You can also use the 3d Paint tool after you unwrap the UV's, to paint on a rough template of your texture on the 3d model, save out that texture map, and bring it into Photoshop to finesse.

Hope this helped you even a little.


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