Multiple UV Islands for Unwrapping a gun to be used in a game

I am wanting to texture a rifle for a solo project I am working on. I have the Hi-Res and Lo-Res modeled. I unwrap the Lo-Res using Smart UV Project. Now, some of the pieces are really small - so here are my questions:

Can you use multiple UV Unwrapped images for major model pieces (ie upper receiver, lower receiver, heat shield, etc) and import/apply to model in game engine such as UDK? Right now the whole model is unwrapped in one island.

If not, what is the best practice for unwrapping a rifle and then texturing?

Thanks in advance

Well, it depends.

You can use separate UV sets for different pieces, assuming your game engine or renderer supports multiple UV maps. Another method is to make multiple tiles on the same map by putting tiles off to the side of the map and using a different image on each tile. Or you can just use one big map on a single tile.

No matter how you do it though, that means loading more pixels, and for a game those all have to fit in GPU memory. Personally, I’d just use a single tile for a rifle because you usually don’t need THAT much detail on them, unless you have some particular restriction on max resolution.

Btw, terminology bit: “island” or “shell” normally refers to a single connected chunk of UVs, “tile” refers to a grid square (the grid in the UV/image editor shows you the 0-1 tile on the current UV map, for example). Smart UV Project (usually) generates many islands on a single tile.

Good deal. This helped a lot - thanks.