Hi, No one is quite getting this.
I started out with a load of points and a few curves for both port and stbd side of an aircraft fin.
I selected them all and grouped them.
A few days later I carry out a careful selection of all those on the port side, then go Modify Copy InPlace and group the result.
I drag that aside and mess around with Patch command and skin it as best I can. (wish patch was a better command)
I now wish to try patch on stbd side. Why mess around for hours I think to myself using Cntrl and shft and mouse clicking trying to select all the points in the original group which occur only on the stbd side when I already have port side selected as a group, maybe I can use this port side group in conjunction with the original group which has both port and stbd points etc, in some kind of subtractive way, to give me the stbd only stuff.
Admittedly I did move aside the port side group but I could move it back dead easy as I used move R0,2000 so R0,-2000 would do that !