1. Reference problem

1.1. Geometry of the problem

Work is being done on a single tetrahedral reference element shown in FIG.

Figure 1.1-a : Tetra reference

We will define 3 normal « level set » in succession, such that we come back to the cases of cuts that we want to test.

Note that the 3D cutting configurations that are tested below are the extension of the 2D case represented above (Figure). All of these configurations can only occur in XFEM quadratic.

Figure 1.1-b : lsn « grazing » in 2D