Sliver Tetrahedron

A sliver tetrahedron is a nearly flat tetrahedron whose four vertices lie near a plane and project onto it as a convex quadrilateral, without any polyhedron edge being particularly short compared with its overall size (Cheng et al. 2012, pp. 12-13 and 25-26).

Its volume can approach zero while the lengths of all six edges remain bounded away from zero. Its dihedral angles can approach zero and , so comparable edge lengths alone do not ensure good mesh quality (Cheng et al. 2012, pp. 12 and 26). Slivers are one of the nearly flat types in qualitative tetrahedral mesh classifications (Hannukainen et al. 2017, p. 3).