About taking a photograph of a building, I use that technique. Take the photo, create the mask, create all possible variations of masks with the architecture of the building. Use the new mask global module (I recently discovered its possibilities when mapping), it fixes the image (position & scale), you do not have to arrange each and every mask into a layer just change them freely and dont have to worry about erasing a layer mask (which happens a lot in the heat of the vjing moment)... and simply concentrate on creating the righ textures for you set =)
I recently did the first monumental live video mapping in Honduras, (first ever in its history of my country!) and used this logic for the mapping of the building.
No se quien soy, pero se de que huyo. M.Montaigne
Twitter: @popversus / @esegabbo