rkv104, I had a quick look at your code.
I think you wrongly place skirts, because HomePieceOfFurniture objects coordinates should indicate the center of the object, not one of its corners.
By the way, may I recall you that the length between two points can be easily computed with Point2D distance method and the angle of a line with Math atan2 method? That would make your plugin much more useful!
If you want to take into account doors placed in walls, you should inspire yourself from Wall3D createWallGeometries that computes this data too.