In the case of Thermo-Photo-Voltaic Cell, When it comes to the establishment of symmetric boundaries, as follows(（http://cn.comsol.com/model/thermo-photo-voltaic-cell-494） ): Symmetry 1 1 In the Physics toolbar, click Boundaries and choose Symmetry. 2 Select Boundaries 1–6, 8, 11, 15, 16, 18, and 19 only
However, the program shows that all boundaries are not available. What is the reason for this? Has anyone encountered this situation?