I need to perform mesh adaptation on a nozzle, which would require me to employ a prismatic boundary layer. I believe mmg3d should be able to preserve the prismatic elements. However during the mesh generation process I realised it would be quite hard to avoid the use of pyramids to connect the outlet of the nozzle to the tetraedral domain.
Would it be possible to preserve also pyramids?
Indeed, Mmg doesn’t allow to preserve pyramids.
Since the version 5.4.1 of Mmg you can provide and preserve “orphan points”, i.e. points that are not connected to the mesh if you specify these points as required.
The only thing to take care about is that the vertex numbering may change when you recover the points after a Mmg call: a way to solve this may be, for the pyramid vertices, to store the initial vertex indices in the vertex reference. Thus, you will be able to map the output numerotation with the input one.
I hope that it will help you.
Thank you a lot Algiane.
So just to be sure I understood. In the .mesh:
- I delete the pyramids.
- I set as required all the 5 vertices of the pyramids.
- I save the index of these required vertices.
- I re-write my pyramids in the mesh.
My doubt is: shouldn I need also required edges/triangles (together with required vertices) ? Will mmg3d know that those points are connected to other elements’ vertices?
You have perfectly understood and yes, you will need to set required triangles (it should be sufficient) for triangles at the interface between tetra and other kind of elements (for prisms, Mmg do that automatically).