How can I edge Loop on a mesh?

Hello all. I’m trying to do something that is fairly simple in my head. I just want to edge loop around a mesh cube. All polygons are quads… but when i try to insertEdge and slide it into place. Rhino trys to insert the edgeloop on faces I don’t want it to and adds triangles… See video. Any advice. I feel like this should be a really simple process… In the beginning of this video I just draw a generic curve to show approximately where I want the loop. And then try the insertEdge

Hi @Drew_Weininger
The edges aren’t considered a loop in Rhino (or at least the are considered to be shared with the adjacent face), so you’ll have to change the type to Ring and go from there. As soon as you have a “fully” internal loop, you can use the Loop type - See video for details.
HTH, Jakob