People tend to see Maya’s UV tools as a last resort, but in this tutorial I hope to show you how easy they are to use and how you can get great results in a short amount of time. Yes, there are loads of applications out there to help you achieve the perfect set of UVs, but once you’ve spent your hard-earned cash on Maya, why shell out any more?
To answer Jeremy’s question and demonstrate the UV Texture Editor, I’ll apply UV mapping to a basic model of a head. But before you apply UV data to any model, it’s best to first assess the geometry to see whether you can cut any corners. In this case your head model is symmetrical, so you could potentially delete half of the geometry – meaning you’d only need to UV one side, and then mirror the model and UVs once finished. Initially, this may seem like less work, but in fact you could be creating more. So instead, keep the model whole and focus your attention on the UVs.
Start by applying a generic set of UVs – something you can work with. Select the model, go to Create UVs > Planar Mapping, and open the options. You want to project your UVs from the front of the model, so select Z Axis as your projection plane and click Apply.
You should now see the new head UVs in the UV Texture Editor, but there’s a problem: the UVs at the front and the back of the head are overlapping. You can see this more clearly if you apply a basic Checker Map texture to your model. The texture will look fine from the front, but will be stretched down the side of the head, and then inverted at the back. In short, the UVs are still unusable. What you need to do next is peel the UVs out from behind the head, laying them out flat so you can see both sides.
Select the edge loop that flows vertically around the model, essentially cutting the head in half. Now deselect the edges at the very front, from under the chin to just above the temple. What you’re doing here is marking which UVs you want to cut, creating a seam that you can later open.
In the UV Texture Editor go to Polygons > Cut UV Edges. With these cut, and the back of the head separated, you can now unfold the UVs. Don’t rush in and allow Maya to go wild on them just yet – that sort of approach will lead to tears. First, select UVs down the centre of the face, starting at the forehead and ending under the chin – in effect, the opposite of what you selected when you cut the UVs.
Now right-click the UV Layout button in the UV Texture Editor. This will open the options for you. Make sure Unfold Constraints is set to None, allowing Maya free rein to place the UVs where it sees fit. Also, make sure Pin UVs is checked, and Pin Selected UVs is enabled. What this will do is make sure the UVs down the centre of the face, which you’ve selected, are left alone, anchoring them so they don’t move. Now click Apply and watch the magic. Your head UVs will be unfolded for you, pulling the back out to the sides, giving you a much better layout to work with. By pinning the central UVs Maya has a good reference point to work from. Imagine it like this: you have a screwed-up towel, and you hold two corners with your fingertips. As gravity pulls the towel down your fingers pin the corners, meaning it falls in a more controlled way and unfolds nicely. Just holding one corner would give a different result, whereas holding none will give you a crumpled mess. As with the towel, Maya also needs some points pinning.
Things don’t end here, though. With this initial layout to hand you can continue to tweak the UVs using the UV Smudge or even the Lattice tools to get the optimum coverage.
Prevent holes from collapsing
Are your holes collapsing?
If you have holes in your model you’ll notice that, once unfolded, the UVs around these areas won’t unfold correctly.
Temporarily fill in the holes
This occurs because there’s no geometry in these areas. Before you unfold, use the Mesh > Fill Hole tool to close the gaps.
Ready to unfold
When you now unfold the UVs, Maya has more to work with, meaning the areas around the holes retain their shape.
Antony Ward has been developing games, building rigs, and animating since the 1990s. He’s worked for some of today’s top game studios