What’s the difference between AUV and GUV tiles?
AUVTiles unwraps every polygon separately on the texture map. With default settings, each tile receives the same amount of texture space regardless of the difference in polygon size.
GUVTiles unwraps groups of polygons, creating the largest groups possible that won’t result in texture distortion. This usually gives better results although it doesn’t always make the most efficient use of map space.
The new PUVTiles takes things a step further by also working to make the most efficient use of the total texture space. This will give the cleanest unwraps while also wasting the least possible amount of texture pixels. You’ll be hard-pressed to find a more efficient, distortion-free mapping method.