Gmsh help: convex hull and offset mesh

Hello everyone,

I know that this is not a gmsh forum but I hope that someone can help me anyway.
Starting from a surface/solid faces/2D mesh I would like to create a convex hull around the surface, then an offset surface, starting from the hull. See:

Sorry for the handmade image, if needed I will do a better sketch.
Are these operation possible in gmsh?
If not, do I need to perform them in a CAD software and then mesh it?

As always, thank you very much.