Flatten instead of mask

When adding the realitymesh to a design, it is possible to flatten curtain part of the mesh. Just add a fence, choose flatten and at that spot the mesh is still visible, but flat. The boundary makes everything in between a shape. Option is to add a elevation with the same result. Now when there is clutter in de mesh, one can flatten that spot by drawing lines at which the mesh is reshaped. Not the 3XM, but only the attachment