How to Make Skins for The Sims
Part 4: Making a UV Map

"This hideous mess is the UV map for the b970 body that Richard made. The three-dimensional body mesh is made up of triangular faces. Each face is defined by three vertices. The UV map defines how the BMP file fits onto all these triangular faces. You can make some really nice skins without ever having to resort to a UV map, but I have no doubt that I'm going to need it to get everything lined up for this skin.

"The UV map is exactly the same size as the standard BMP file for a Sims skin, 256x256 pixels. You can see that the character's arms are on the left side of the map, her back is in the middle, and her front is on the right-hand side.

"If you look closely you can see where the facets are that define the edges of her vest, as well as all the more interesting anatomical details. Now that I've shown you what it looks like, let me explain how I got it.

"I don't have a handy 3D meshing utility on my Macintosh, so I had to start up Windows for this one. The program I'm using is called Bodywarp, written by Keith "Spanki" Young. (The last time I checked, Spanki's web site at www.bodywarp.com was off line. If he doesn't come back, perhaps you can talk someone into sharing a copy of the program with you. Spanki distributed Bodywarp as freeware.)

"Here's Bodywarp in action. I have loaded Richard Ward's b970 mesh into and mapped his Rogue skin. For this run it doesn't matter what texture BMP I use because I'm only interested in the UVMap that Bodywarp can create. While I'm here I can get a closeup view of the mesh. It looks like the vest will have full sleeves, which is just what I want for my toreador!

"Now that I have the mesh loaded in, all I need to do is tell Bodywarp to save the UVMap. There's a convenient command for this under the File menu. "While you're in Bodywarp you might play with all the other commands to learn what it can do, but for now all we need is the UV map. When you choose this command, it brings up the dialog for the UV map settings.

"I just use Spanki's default settings for the map. The size, 256x256, is just what I need to put this map into the Photoshop file where I'm building the character's skin. I'll copy this and paste it into my Photoshop document as another layer so I'll have it as a reference any time I need it.

"Before I get into working on the toreador outfit, I want to show you something important about how the UV map ends up on the body. To do that, I'll add some more color to the UV map so we can see what's where. Now all I need is a victim ... er, rather ... a volunteer!

"Hey Caddy! C'mere!"