Labels after Remeshing

Hi there!

I’m sorry, I know things like this have been asked before, but I don’t seem to understand the answers, since I can’t get this to work :confused:

I’m using parmmg3d inside FreeFem and have the following problem:
When I remesh, the labels get all messed up. In places where I’ve had label 1 before, it has something else and where the mesh was split internally, the label becomes 1 …

This is a picture of how it is before remeshing and how it is supposed to be: zero on all boundaries.

These are pictures of how it is after remeshing:

(In the first picture the top should still have lable 1 and in the second picture the interior should not have label 1.)

I have no idea why this happened or how to resolve it.
The command line I’m using is the following:
parmmg3d(Th3ParMmg, metric=hParMmg[], nodeCommunicators = communicators, hgrad=-1, verbose=5) ;
The only named parameters I can pass into parmmg3d are:
metric, comm ,verbose, mmgVerbose, mem, debug, mmgDebug, angle, iso, lag, opnbdy, optim, optimLES, noinsert, noswap, nomove, nosurf, anisosize, octree, meshSize, metisRatio, ifcLayers, groupsRatio, niter, angleDetection, hmin, hmax, hsiz, hausd, hgrad, hgradreq, ls, requiredTriangle, localParameter, nodeCommunicators, neighbors.

I appreciate any help, thanks in advance!


Are the labels attached to the nodes? If yes, they are probably modified to build the parallel communicators between mesh partitions. Mmg, as well as ParMmg, don’t warranty the preservation of nodes labels but in general, the user can reconstruct this information from the faces or edges labels that are preserved.

Best Regards

Hi Algiane,
Thanks for your response. I don’t know if the labels are attached to the nodes, I would have to ask on the FreeFem forum.
By reconstructing the information from the faces or edges labels that are preserved, you mean that I would need to tell the program afterwards which faces/edges I would like to have which label?
FreeFem has a command where, to my understanding, you can tell which labels should change to what value.
The two problems I see there is that the interior is on the same label as the boundary (red in the picture above), so if I change either, I persume I will change both and the top and bottom are on no particular label (blue in the picture, has a high negative “label value”), so the program wouldn’t know which faces/edges I want to change.
But I guess this is something I also need to ask in the FreeFem forum :slight_smile:

Hi Algiane,

I just wanted to let you know that this was an error on my side, I did something wrong when defining the labels and also when looking at the labels. It’s all working fine.

You can close (or even delete) this thread.
Thanks again for your time!

Thanks for the feedback,

Best regards