I’ve been importing some manufacturer models (.igs) and a lot of the faces are showing as back faces. I have a plugin in Sketchup where I just mouse over the back faces and they flip. I think I also had a flip all back faces plugin also. Any such thing for Rhino? Selecting all the back faces one by one will be a nightmare.
You can typically join all the adjacent faces and the normals will automatically unify. You can then flip them globally (if needed) with the flip command.