Hello forum

consider the case of a non manifold solid, made of two cubes sharing a portion of a face.

See Fig. 1.

Let the shared face, for simplicity, be a square.

See Fig. 2.

If I mesh the initial non manifold solid the mesh at the shared face is obviously conformal,

since a unique triangulation of the shared face is given as input. See Fig. 3, in which some

faces have been hidden)

Now decompose the composite solid in two solids: the two cubes.

See Fig. 4: here the solids have been departed in order to show the boundary of the shared face.

Then surface mesh with mmg the two cubes, one by one, by calling two times mmg.

See Fig, 5 (“Top” cube), and Fig, 6 (“Bottom” cube).

The triangulations of the “ex” shared face for meshing the two cube are identical.

See Fig. 7.

I would expect that when meshing separately the two cubes, the grids at the two green faces

should be identical.

It is not: see Fig. 8 (mesh of the “Bottom” cube), and Fig. 9 (mesh of the “Top” cube

Why?

Grazie mille

GiovannicompositeSolid.pdf (109.2 KB)