Synopsis

Refining one triangle often requires the refinement of one of its neighbors.^[33] Refining that triangle can require the refinement of one of its neighbors, too. This process can even wrap around and require the further refinement of a triangle that's already been refined, and ppm2oof can end up in an infinite refinement loop. To prevent this unfortunate occurence, a single element will be refined no more than max_divisions times during one application of a refinement command. If the refinement of a neighbor forces the element to be refined more than max_divisions times, then the direction of the separatrix will be chosen so that no further refinements are required, ignoring the setting of /adaptive_mesh/refine/division.

As a special case, if max_divisions=0, then there is no limit on the refinement. Caveat computor.