how to construct non-convex polyhedra?

[King Yin Yan]

I am looking in the Polyhedra class but the module is for convex ones only.

I can build a non-convex polygon in 2D by listing its vertexes.

I would like to then construct a cylinder with that polygon as base.

Thanks in advance.

[Dima Pasechnik]

it seems that Sage can't do this; moreover, none of its geometry backends
support nonconvex polyhedra.

There aren't many options if you want off the shelf software
supporting these. Nef polyhedra in 2D and 3D are supported by CGAL
(the latter does not have an interface to Sage AFAIK).
I am not aware of anything else (although I imagine there is a lot of
CAD software that can deal with these in dimensions 2 and 3)