MMG3D does not preserve references

[pavanakumar]

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I am facing problems with MMG3D with preserving reference of vertices of parallelTriangles. I freeze the adaptation at these boundary triangles using MMG3D_Set_parallelTriangle. In order to match the frozen triangles with the unadapted mesh I add a integer reference. This reference is not being preserved even though the triangles are not modified.

But I never faced this issue in MMG2D Set_parallelEdge which does preserve the reference of the vertex after adaption. If the reference changes arbitrarily what is the purpose of having this in MMG3D?

[pavanakumar]

An update on the problem. Indeed MMG3D did not change the reference but is adding new ones; in my case it is adding node reference "1". So I added an arbitrary offset say 256 to my integer reference and was able to recover my original integer references (after subtracting 256 and ensuring to check for references > 256). So the question is how does MMG number the new references? Is there a logic to it?

[Algiane]

Hello Pavanakumar,

I am not sure to understand what is modified (and why). If I understand :

• you freeze some triangles using the MMG3D_Set_parallelTriangle function;
• you add an integer reference to the nodes of the freezed area;
• Mmg3d doesn't change the reference of the points of the freezed area;

Am I right?

If yes, normally, Mmg isn't allowed to insert new points in the freezed area so I suppose that the points of reference 1 are located outside this area? Are they on the surface or inside the volume? It will be very helpful if you can attach a small test case that reproduces the problem.

Regards, Algiane

[pavanakumar]

I am working on the minimum 3D mesh and will post it soon. The one I have right now is not sharable.

[Algiane]

Hi @pavanakumar ,

Do you still have issue with the reference preservation or can I close the issue?

Thanks by advance, Algiane