Sometimes you want to extrude the border and connect to another plane or mesh,
but there isn't a good way to do it,
live snap and transfer attributes won't give you good results as they are snap based on the closest distance or face normal direction.
poly border projector - project border to target mesh with 3 different methods
1, Axis - extend with a single axis, it can be World or Local space.
2. Extend - extend along the edge direction
3. Extrude - extrude and extend along the edge direction.
usage: select some edges or vertex shift select another mesh then click a button.