UV Mapping - How to use multiples materials and images for one object

[Nova]

Lets say you have a model with 2 materials, metal and wood. You go through the AutoUV tool and it creates a new material that everything gets assigned to, you no longer have metal and wood. But if you have gone Material>Select and made a new selection group for each material, then after the creation of the new material you select one selection group and re-apply it's old material, then do the same for the other.

If this was a complicated model, and you hadn't saved selection groups, you would have to reselect the faces you wanted to be metal and wood respectively once more. Saving the selection groups skips that step.