I have an overhead track plan (a blueprint without actual dimensions) for an existing roller coaster that I'd like to recreate. Is there a way to temporarily lay that track plan on the ground in order to build the coaster on top of it, and then finally delete the drawing?
Yes, sort of. A friend of mine actually used the large Billboards and put them on the ground then built the coaster on top of them. Of course he deleted the billboards when finished.
The trick is to edit the blueprint into smaller "chunks" to fit the billboard.
Look here: https://www.youtube.com/watch?v=h4k5vJ9DMM4 to get a look at what he did.