@techreport{oai:ipsj.ixsq.nii.ac.jp:00032670,
 author = {Herbert, Edelsbrunner and Herbert, Edelsbrunner},
 issue = {98(1989-AL-012)},
 month = {Nov},
 note = {We study three types of spatial triangulations: Delaunay triangulations  triangulations with non-obtuse dihedral angles  and KJ-triangulations. The latter satisfy a certain angle condition useful for finite element approximation. We show that the condition for Delaunay triangulations is incomparable with the other two conditions  and that triangulations with non-obtuse dihedral angles are necessarily also KJ-triangulations. These relationships are in sharp contrast to the ones in the planar case., We study three types of spatial triangulations: Delaunay triangulations, triangulations with non-obtuse dihedral angles, and KJ-triangulations. The latter satisfy a certain angle condition useful for finite element approximation. We show that the condition for Delaunay triangulations is incomparable with the other two conditions, and that triangulations with non-obtuse dihedral angles are necessarily also KJ-triangulations. These relationships are in sharp contrast to the ones in the planar case.},
 title = {Spatial Triangulations with Dihedral Angle Conditions},
 year = {1989}
}