The Marching Tetra Multigrid Method combines adaptive Multigrid refinement and
multipart Marching Tetra meshing. This Method was presented at the Nafems World Congress 2019. →
NWC 19 presentation
The MMT level 0 mesh is simply a single → Cubic Tetra
The → Introduction shows MMT input and the corresponding results.
It is impossible to mention all related work. An internet search with the keywords
"BCC finite element quality multipart multigrid mesh" gives an impression of how busy this field of research is.