Also, can you add a grid texture with circles and a per-pixel grid? Maybe the one here with the big R... http://wiki.polycount.net/TextureCoordinates#UV_Map_Grids
Thank you guys for the nice comments. @Abdullah: The packing function does not snap to grid. Instead it uses pixel units for the padding between the Shells. This ensures a better consistency in the Shells distribution. @Norstu It is a free upgrade for all current customers. If you owned PolyUnwrapper 3, you should have…