Getting Started with UVs in Maya

In this lesson, we'll take a look at relaxing and unfolding UVs to minimize distortion. So in some cases, we may have our UVs laid out. But there may be areas of distortion. So if we look at this particular model, the dinosaur, we can see that along the back we've got some distortion here. If we look around in some of these other areas, we'll probably find some distortion as well, maybe on the arm, over here on the leg. So it's easy to see when you're using textures like this that have a kind of a grid pattern to see distortion like that. So looking at that we need to kind of fix it. So one of the things that we could do would be to come in here. And if we select this leg, for instance, so that's going to be located right up here, one of the things that we could do would be to just manually manipulate the UVs. So maybe grab those particular UVs right here and kind of move those back up. You can see that that helps with this area down here if we can maybe take these and start to move these around a little bit. So we can kind of somewhat affect our UVs in a positive way by just moving these around manually. But it's going to be pretty tedious to fix any large areas and to get them looking like they're supposed to look and fix them up. The idea is that these faces should be about the same shape and size as the faces here in our 3D view. For instance, if we have a long thin polygon here, if it's short and fat in the UV layout, it's not really matching up. So it's taking all of this texture information from this small area and stretching it across this large area in our 3D view. So ideally we want to have our faces in our UV texture editor match up pretty well with the faces here. So there are a number of ways that we can kind of relax these UVs. We could select the group of UVs that we want to affect. We could go up here. And this is in our UV Texture editor that's just docked here. So we can go to Polygons and go to Relax. We can relax those. And you can see how that spaced everything out. It doesn't match up. We still have the distortion here. But in our UV Texture editor, you can see that they're all spaced out nicely. So it's this versus that. So relaxing can be a good way to just take a jumbled mess and just kind of relax it out so that you can manipulate it. If we go into the options, there are not a lot of options. But you do have the ability to pin the UV border. Or you can pin anything that's not selected. So you can pin just the selected so you can relax everything but that and so forth. You also have the maximum number of iterations that you want to do. So a lot of times we'll do a pin UV border so that the border of your shell doesn't really change. So those are the options that you have there. We also have the ability to unfold our UVs. And this can be found here under, again, with UVs we've got Relax and Unfold over here. We've also got them in here so Unfold located in here. And this will actually do a little bit better job of matching up the polygons here. So if I take a large selection of UVs and the button for unfold is just right in here and I unfold that, you can see how automatically and how quickly that matches those polygons up with the polygons here. And we get a much better result than even working with Relax. So in any areas of distortion, we can use Unfold there. So if we open up the options to unfold, we have some weighing options which we won't really talk about right now. We also have the pinning options. So right now we've got the unselected UVs pinned. And then we've also got the maximum number of iterations. So if you want to make this a very gradual shift, you can decrease the number of maximum iterations so that everything doesn't happen at once. You may have to apply it a couple of times to get the result that you want. We can come up here to the back for instance. And so that's going to be, if I select that, it's going to be right up here. So you can see all of the polygons we have here. So I'll just select some of these. And we'll do a simple unfold. And you can see how quickly that pops into shape. So even thought it's at an angle, you can see they're not really deformed. They actually look pretty good. Again, we can go up here on the front arm. Looking at these we could manually come in here to tweak these out. Let's try working with a smaller value here in our unfold. We'll go down to maybe 100 in the maximum iterations. And let's go ahead and apply that. And so in this case it worked pretty well. Let's kind of bump that down a little bit, try maybe 10. So with 10 you can see we can start to do it a few times. And it gets closer and closer. In this case, it's not really doing much. So we'll take that all the way down. So two, let's apply it once and then apply it again, apply it again. So with a lower number, you maybe had a little bit more control over coming in and modifying those. You can select other groups and unfold those. You can also select the entire shell. Keep in mind, though, for instance, things like these fingers. If we were to go in and unfold these, these actually look OK. But a lot of times the fingers that you have will start to overlap or you'll have areas that are close when you unfold them so right down here start to overlap. So you just want to be careful of that. And you want to make sure to avoid that overlap. So that's just something to think about. But unfolding is a really valuable tool, especially when you're auto mapping and you're coming in and you're sewing stuff together and it's not always going to look right. And so then you take that shell or that group of points and you just go in and unfold it so bringing that in and unfolding these different areas. And we can do these a section at a time if we want to. We can come across and just unfold these and hit it a few times to just unfold it so it looks a little bit better and removes that distortion from our UVs. So make sure to check out relax and unfold when you're working with your UV shells. So the next thing that we want to talk about is how do we transfer UVs from object to object. So let's say we've created a UV on one object, a UV layout. We have another object. And we'd like to transfer that, use the same UV layout for that object instead of laying out each object individually. Well, we can do that using some functionality here in Maya. So we'll take a look at that tool in the next lesson.