I’m not getting that message at all. It works fine when I select the group with the guidepoints. Did you explode the components containing the guidepoints inside the group?
Here’s what I get from your point cloud. The skirt is initially made as a group separate from the terrain but after exploding it, the object is a solid group.
It’s a a bit off topic to your main issue, but I’d strongly recommend you learn to work in perspective instead of parallel projection. For 3D it is much more realistic and intuitive!
Thank you Dave that was exactly it, I always forget if you have you regroup after exploding the componants or not with Topo Shaper. After some playing around it’s working as expected. Thanks so much for your help, saved me a headache here!