This option only works well on WHAT IF generated maps, or maps scaled such that the values fall in the -115 till 115 range. Other maps will cause this option to produce strange error messages. If followed by the IN50 option the map can be made such as only to show completely internal cavities upon contouring. This option is VERY time consuming. And besides, the PEEL option virtually does the same.
Convex points are grid points that form a sharp external protrusion in the map.
They have more empty than filled points around them. In practice they are defined as points in the shell with three or more orthogonal neighbors that have the value zero. The option got its name because it removes the points that are at a convex surface. This option only works well on WHAT IF generated maps, or maps scaled such that the values fall in the 0 till 100 range. Other maps will cause this option to produce strange error messages.