generation of an elliptic paraboloid

I would like to generate a surface that is a part of an elliptic paraboloid but after several attempts, I failed. My goal is to mesh the volume inside.
If it is possible to generate such a surface with Trelis, what is the strategy?
Thanks in advance,

I’m not sure if this is what you are looking for

create vert 0 0 0
create vert -1 1 0
create vert 1 1 0
create curve vertex 2 vertex 3 vertex 1 parabolic
split curve 1 fraction .5
delete Curve 3
sweep curve 2 yaxis angle 360 steps 20