Selects all faces that have one or more vertices which deviate from the average plane formed by the face. Any faces detected by this operation will have at least 4 vertices, since a triangle is always planar. Nonplanar faces are an ordinary part of typical geometry, but in some specific cases, they may be undesireable.

The threshold for nonplanarity is very small and not currently configurable. This is planned to change in the near future to allow for some nonplanarity tolerance while still detecting more extreme deviations from planarity.