The gist of UV mapping, very basically, is that you take the various shapes that the mesh is made of, and spread them on a 2D surface, which will then fit the texture itself. If the mesh is a single compact object, the unwrapping will usually produce a strange result, which in fact is created by the program trying to spread the map in only one seamless shape. You'll want to avoid this and instead rely on multiple parts (though still a single mesh), that in the UV map are detached from each other, so to have a clearer idea of what is where. To do this you'll need to play around with seams: they are basically marked edges that tell the program to split the UV map on those edges. Here's an example with a simple UV Sphere in Blender: All apparently normal, but the resulting UVMap is completely unworkable: So we're going to use seams on the edges of the sphere, which appear on the mesh as red-colored edges (note that you're not forced to follow any specific direction or shape for the seams): And this is the far more acceptable result after unwrapping the sphere with seams: One last thing to take care of before exporting as a .glm model: you have to split the seam edges, or you'll incur in the "UV Seam found!" error: Be careful though: splitting will literally double the number of vertexes affected by the split, as you can notice, and will also show a (minor) artifact in game due to the mesh being split (which can't really be helped with anyway): Hope this helped you a bit.