It is necessary to produce boolean subtraction. Source finurs: cubes (or the simplest volume letter "T"), planes (up to 10 corners, including non-convex). Poligonazh minimum for such figures. Subtractions are made in realtime. With one mesh there can be 6-8 consecutive subtractions.
Simple examples of use:
1) There is a room with six walls and a floor plane. It is necessary to cut this plane along the walls to get the floor of the correct shape.
2) There are ceramic tiles on the wall. It needs to be cut along the border of the wall and along the border of the doorway simultaneously. If the tile on the floor is simply cut along the border of the floor (the floor can be a non-convex polygon, the tile can be divided into two parts as a result).
Now this plugin is used: https://github.com/karl-/pb_CSG Unfortunately, sometimes it hangs up the application without debugging information and gives artifacts. I myself am not friends with calculations, writing something of my own is hard.
Can someone advise other solutions?