Re: [Getfem-users] Delaunay triangulation of level set cut mesh

[Yves Renard]

Dear Wen,

Yes, the mesh_level_set object performs most of the job : on each element cut by the crack, a certain number of intersection points are computed (the density of computed point depends on the curvature of the level set). Then Qhull is called to obtain a sub-mesh of the element conformal to the crack (or any set of level-sets). Some verifications are performed : if the obtained mesh is not conformal to the crack, more intersection points are computed.

Additionally, the sub_mesh is stored by the object mesh_level_set and can be extracted (cut_mesh() method). If there is a lot of cut elements, it can be a bit expensive in term of memory (but not so much in practice) but it is necessary for post-treatment : it allows  to interpolate the solution on a cut-mesh before drawing it.

Yves.


Le 23/11/2016 à 16:44, Wen Jiang a écrit :

Hi,

I am interested in how getfem++ uses the qhull library to do the triangulation of the mesh which is cut by a level set function. I have two questions,

1. In 3D, the crack front could terminate within the element and it is easy to know which element contains the crack front based on the level set functions. But it is not clear to me how to use qhull in conjunction with level set function to do the sub-triangulation. Does getfem need to find the points along the crack front somehow from the level set function?  

2. Getfem can integrate quantities along the interface (3D is surface, 2D is line). Where does getfem store these surfaces/lines that are generated from triangulation by qhull?

Thanks,

Wen

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  Yves Renard (address@hidden)       tel : (33) 04.72.43.87.08
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