Loft 2 mesh edges to create 1 closed mesh

I’m trying to loft this 2 meshes to create 1 closed mesh for 3D printing, but without any success.
Any suggestions on how to do that?
Thanks a lot!
loft mesh (19.0 MB)

The inner mesh seems to be a cylinder. Instead of lofting the edges, you could also cap the outer mesh and subtract a meshed cylinder… (14.5 MB)

which plugin did you use?
I dont have this component

That’s a script in Rhino 8.

private void RunScript(List<Polyline> P, ref object A)
    Mesh result = new Mesh();
    foreach(var poly in P)
      Mesh temp = Mesh.CreateFromClosedPolyline(poly);

    A = result;

Can I use it in Rhino7?

I’ve used the same code in Rhino 7 but you’ll have to do it yourself. I’m not working with Rhino 7 anymore.