NURBS Texturing
General Maya Tips and Strategies #2

As talked about in my UV Mapping tutorial, polygons' UVs are able to be mapped and situated on the texture in order to achieve a desired look. NURBS are different. NURBS utilize their CVs as UVs, and it's not always plausable to adjust CVs for texturing without screwing up the mesh shape. Therefore, for NURBS, you have to create the texture to fit the object, rather than fit the object to the texture as in polygons. This can be a very tedious process. A strategy for this that I've utilized is really quite simple, and makes the process go faster.

The scene I'll use is the Hero model from my 3D Stills gallery. We'll concentrate on the lower left abdominal region (Fig 1).Figure 1
Remember that our objective is to create a texture that has been designed to accomodate the NURBS surface. In order to do this most effectively, we need to mark the texture with visible guidelines that we can follow. In order to do this, I'll use the 3D Paint Tool. It is located in the Rendering Subset under Texturing>3D Paint Tool>Options. Select the tool with the object selected in order for the tool to affect it. Here's what the tool options look like: Fig 2.Figure 2
First of all, go to the File Textures section. Select Color for Attribute to Paint and choose a format. You want to choose a format that can be read by Photoshop. I'll use .jpg. Once these settings have been chosen, click Assign Textures. Choose the texture resolution you want. I'll go with 256. Click Assign Textures. This will assign a new material to the object with a file mapped to the material's color. (Fig 3)Figure 3
Now, go to the Color section. Choose a color and begin to mark your object. Since my example is a muscular superhero, I'll mark the major muscle groups in order to create realistic texture shadowing. On your object, you'll want to mark where anything would be in the texture, such as pockets, seams, etc. (Fig 4)Figure 4
It's also a good idea to mark the direction, such as which way is Up and so on. You'll understand why, soon. (Fig 5)Figure 5
When you've marked it how you'd like, hit the Save Textures button under the Assign Textures button in the 3D Paint Tool Options box. It's important to make sure your project has been set so your texture will save to your project directory. Once saved, open the image in your favorite image program. I'll be using Photoshop. Here's how mine turned out: Fig 6. As you can see, we know it has been rotated because of our direction mark.Figure 6
Now, using these markings, you should be able to know where things are on your model in relation to the texture file. For my example, I'll just use colors. (Fig 7) Once you're done, save your image. I would recommend saving as a .tga file. If you do so, remember to add an alpha channel!Figure 7
In Fig 8, you can see how using the 3D paint tool markings, you can determine exactly how your texture needs to look for your model. What's neat about this is you can use the same process to create other maps, like bump, specular highlights, etc.Figure 8
I hoped this helped you understand how the UVs of NURBS work a little better. As usual, let me know if there's anything you think I should add, change, etc. by emailing me. :) Good luck!

Michael McKinley