Here is a trick for dividing rooms using an inside wall as an anchor point.
- Select a point on your inside wall, conveniently close to an outside wall where you would like to divide an existing room.
- Using a solid piece of material (cardboard, plywood, boxes, whatever) as a temporary wall, span the distance between the exterior and interior wall.
- Remap the floor, especially on both sides of the temporary wall. Make sure there are no gaps in the temporary wall the Lidar can see through. (Remove temporary wall after remapping.)
When the mapping is completed, the algorithm will now treat the inside was as an outside one, and it can be used to divide rooms. You will also end up with a permanent room break (wall) where the temporary wall was.