Open boundary remeshing

By default, mmg3d considers input triangles as boundaries if they are either:

• external boundaries delimiting the mesh.

• internal boundaries, i.e. at the interface between two different domains.

Any other triangle at the interface between two tetrahedra with identical references specified in the input mesh is deleted during mesh analysis. However, it is possible to preserve such triangles using open boundary remeshing (-opnbdy option). In this example, consider the input mesh island.mesh, illustrated below.

Open boundary: references are identical on both sides of the yellow surface

To preserve this boundary, run the following command:

mmg3d_O3 -opnbdy island.mesh

As illustrated, the open boudnary is not deleted and is remeshed at the same time as the volume mesh.

Remeshing with -opnbdy mode

Note that open boundary remeshing is slower than standard remeshing.