How can I create a plane with one smoothing group?

Currently I use ProBuilder to create a plane and I realise the plane has several different smoothing groups. So I need to open Smoothing Group Editor to set something.

Can I create a plane with one smoothing group?

 

Ok, I get it.

Code (CSharp):

1. foreach(var face in pb.faces){
2.     face.smoothingGroup = 1;
3. }
4. pb.ToMesh();
5. pb.Refresh();
6. pb.Optimize();