"Geometry.Rotate" The rotation of the problem

For selected objects, how to rotate the selected object.
IEnumerable Sel_obj = doc.Objects.GetSelectedObjects(false, false);
Every object in the traversal of “Sel_obj”, then “Geometry.Rotate” to perform a rotation, in the Rhino object is not rotating, why?

In the example below objects are translated; rotation can be done in a similar way. Basically: don’t transform the geometry, but transform the object that contains the geometry.

If you transform the geometry you have to use doc.objects.replace the old geometry. If you have an ObjRef you can transform the object directly.

Thank you very much.
The problem has been solved