The first step in good UV layout is to create a duplicate, "averaged" version of the mesh. This is a version with potential cavities or overlaps removed by smoothing out the mesh. Common places to focus on are the ears, eyes, nose and mouth since these create natural creases and cavities in the face. We used Maya's "Average Vertices" and "Sculpt Polygon" tools to achieve this. Once again, it is important not to add or subtract points or edges at this point.

        
The head on the left is the original mesh. In the middle is the "averaged" mesh.



This is the UV layout achieved through applying a cylindrical projection map to the averaged mesh.

It is much easier to project UV co-ordinates onto a smooth mesh. There are a number of different ways to automatically project UV co-ordinates onto a mesh, but they are so software specific, that I'll just say that we used Maya's cylindrical projection and leave it at that.

The aim in this process is to create a two-dimensional layout of the mesh where the sizes of the squares on the layout proportionately match the size of the polygons on the mesh. In places where the squares on the UV layout are proportionately larger or smaller than on the mesh, texture "stretching" will occur.

Once we'd achieved a satisfactory results, the UV layout of the "averaged" mesh was transferred back to the original mesh

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