Combining and Subtracting Physical Groups
I have a very simple problem but can not find a solution to it. I have 2 Physical Groups. One that contains all Surfaces of my 2D Model and one that only contains a sub-group. So there are Surfaces which are included in both. My goal is to "subtract" the sub group from the whole group to get a third physical group (Main Group - Sub Group = Third Group ). After that I would like do delete the maingroup to have 2 Physical Groups left. Thank you in advance!!