As you can see in the video below, I can’t select a ring of edges around the blue shape, but only all the edges of one of the segments. Even when I join (which it already was) the segments it doesn’t work. Is there some setting I can use so I can change what I want to select? And which setting should I use in this case? I’m using rhino7 on a macbook.
post the file so we can have a chance at helping.