Would you think the system would just interpret the scan in terms of simple line objects, then let the user tweak each line accordingly? I wonder if it would speed up the process, and make it seem a bit more magic, if you could say "I want to make a platformer," and then all the lines are interpreted as floors. If you say "Let's build a dungeon crawler," it changes to top-down mode and lines are all walls. In fact, for a simple proof of concept, that's probably as much as I'd recommend building right there, and adding more functionality to it later. Still, it's worth throwing all sorts of ideas out there.