Reply To: Using periodic BC in DGTD

[Guilin Sun]

I think it is not due to periodic, it is due the meshing of spheres. It can be challenge meshing curved surfaces when two spheres are cut or very close. You may need to use very small edge min. You can also try to first disable the smaller spheres.
A side note: this current setting of periodicity does not qualify the periodicity, as a standard periodic structure duplicates its unit cells by the periodic BCs. When you duplicate the current settings, the geometry will not duplicate its self as expected since the spheres are not cut at the symmetry. Please modify the periodicity in order to get correct result.