Select specific nodes

Altair Community Member
Updated by Alberto Casas
Hello guys,
I was wondering how to select a group of specific nodes in order to fixed them in all dof. In this case, my geometry is a circle with a diameter of 170 mm. I would like to fix all the nodes that are further than a circunference with diameter of 80 mm, I mean the red part in the next picture. Any idea??
I was thinking of using the quick edit tool and create another circunference with an offset. The problem I see is that I have to edit the geometry creating a new line and mesh again. Is there any way of doing that without having to mesh again??
Thank you in advance!!!