** Note: this will be broken up with images and occasional bits of humor soon **
This post will attempt to explain some of the key points of texture mapping polygonal objects in Maya 8.5. This approach would be one you would use as a beginning 3d artist or as part of a production team that does not have some sort of 3d paint solution
I think it is useful to point out that this technique will inherently cause a bit of stretching of the texture over certain faces of the polygons. It is necessary to unitize your UVs to alleviate that sort of stretching. There will also be some seams with this method. Both of these points we will attempt to minimize by working intellegently. In regards to the seams, you as the modeler and texturer must try to find a way to minimize their visibilty, or use them as logical breaks in the surface you are modeling.
The projection method you would use will depend on the general shape of the model, or you can make a couple of planar projections and stitch together the resulting UVs. The Automatic Mapping method does the best job of laying out the UVs with the least distortion, but does not take into consideration the form, leaving somewhat of a jigsaw puzzle for you to stitch back together.
A common method is to do Planar Mapping of faces and resew the UVs as a flattened out continuous pelt. You want you texture map to make good use of the entire 0-1 quadrant that is visible in the UV Texture Editor. That quadrant is usually repeated or tiled into the other quadrants, but with some advanced texturing tricks, you can assign other textures to those other quadrants or offsets. Another lesson for another time.
Open your UV Texture Editor so that it is visible along with your model in the viewport. Notice that when you have the object selected, the current mapping method of UVs is visible in the UV Texture Editor. When you drop the object there is nothing visible in the texture editor. To accomplish your planar mapping you will select your object, right click it to get to the face component mode and select the faces you want to map. You then go to the Create UVs menu item and choose the Planar Mapping option box. In the Planar Mapping options you will choose the axis that would give you the best resulting faces. When you click the button to Project, you will see the resulting UVs fill the 0-1 quadrant of the UV Texture Editor. You will select these UVs in the editor and move them to side for editing later. You move, scale and rotate UVs in the UV Texture Editor with the same tools you use to edit objects in your 3D viewports.
You would then go back to the viewport, select the next set of faces you want to map, and map them according to the best axis for their orientation. You have the option to map along the X, Y, or Z axis.
When doing multiple planar mapping of UVs, it is very important that you separate the planes you choose intelligently. You want to map planes that face the direction of the axis you are mapping them with. And if your model is not exceedingly simple, you need to devise a way of remembering which row of faces was the boundary of that mapping, since your perpendicular planar mapping has to include the remaining faces. You don’t want to forget to map any stray polygons.
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