could you go through the steps for projection mapping? it sounds like a good way to go.
the reference picture i'd be using is like the one above. for the explosion i think it'll be concentrated on the 2nd/3rd floors of the main building, so it'll explode out, and maybe the roof'll cave in. i think i'll put in an initial flash, so a glow shoots out from all the windows before it explodes. it's a quick shot, maybe...50 frames max. then a cut back to it once it's done, lots of smoke billowin out, so the inside won't be too clear, but it would be cool to see some interior details, maybe some more things fall and collapse...

and again once i've used the split polygon tool to divy up sections of the wall, how do i seperate them? i'm not sure what that action/tool is called.

thanks for your help guys.