# Why does ConvexHullMesh give inconsistent output stuctures?

I know much of the stuff in ConvexHullMesh needs some TLC convexhullmesh-inconsistency

But, can anyone see why this would produce inconsistent output:

Case 1 (expected behavior):

sp = SpherePoints[5];
chSphere = ConvexHullMesh[sp];
chSphere["Faces"]


Case 2 (expected behavior):

rp = RandomReal[{-1, 1}, {5, 3}];
chRP = ConvexHullMesh[rp];
chRP["Faces"]


Case 2 (inconsistent behavior)

dodCH = ConvexHullMesh[PolyhedronData["Dodecahedron", "Vertices"]]

• Surprisingly, if I start from a fresh kernel (using kernel quit) it doesn't work and I get the problem with "Faces". But if I execute in a different cell (and ignore the output of) BoundaryMeshRegion@Dodecahedron[]; then run your code again, amazingly it works. There is clearly some kind of stateful bug in the object ConvexHullMesh produces which is exposed when calling dodCH["Faces"] and disappears after running BoundaryMeshRegion@Dodecahedron[] – flinty Jul 17 '20 at 21:08
• Indeed bizarre. As most of the other "Properties" of MeshRegions. An efficient workaround in this case would be the (also undocumented) MeshCells[dodCH, 2, "Multicells" -> True][[1, 1]]. – Henrik Schumacher Jul 18 '20 at 6:10