That example shows that one can call `CGAL::make_mesh_3` to create the c3t3,
and then change it with a call to `CGAL::refine_mesh_3`. But the second call
is completely optional. Most of the applications will never refine a mesh once
it is created. The example is just a demonstration that it is possible.
Re: Is it possible create c3t3 mesh without changing anything in the criterion?
Thank you for your response. But, in the criteria the parameters change the
mesh even I don't use refine. Like in the picture. the left one is the c3t3
mesh after using the criteria. And the right is the original eight.off file.