Merging coplanar mesh faces fails - succeeds with NURBS

Rhino
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1

In the file below, I have a mesh object - it has 80 faces

Geometry:
Valid mesh.
Closed double precision polygon mesh: 220 vertices, 80 faces

If I run MergeAllCoplanarFaces on it, I get no real visual change, however I see the following in What:

Geometry:
Valid mesh.
Closed double precision polygon mesh: 222 vertices, 80 faces with normals (71 n-gons)

Hmm… So I now have 71 Ngons, most of which are still… triangles. If I run DeleteMeshNgons, I am back to 80 faces, but now I have 222 vertices… Hmmm.

But that is not the main issue. The issue of course is that there are many coplanar faces that can indeed be merged. Run a MeshToNurb and then MergeAllCoplanarFaces and you get… 21 faces

Geometry:
Valid polysurface.
closed solid polysurface with 21 surfaces.

Shouldn’t MergeAllCoplanarFaces do the same on the mesh as with the NURBS in this case?

Tested in V7 and WIP.

MergeCoPlanarMeshFaces.3dm (2.0 MB)

2

In my opinion, merging co-planar mesh faces is pointless, since the topology of the mesh usually is a Gesamtkunstwerk, meaning you want loops that run all around an co-planar islands to be subdivided to make that happen. If anything, merging the co-planar faces will break the mesh topology-wise, by for instance producing a ton of ngons like in your example above, and thus rendering it hard to manipulate afterwards.