Grouped Objects Not Being Output With UnrollSrf

Hello, I am brand new to rhino so please forgive my lack of knowledge of the subject.

I have a box with an open top and a flange at the top. I am using UnrollSrf to extract the pieces and when I do the very top (lip/flange piece) is not created.
Before UnrollSrf

I used ‘Group Objects’ to group the top(flange) and the box together.

Does anyone know why the flange is not being created with UnrollSrf?
boxflange.3dm (65.2 KB)

Thanks in advance for any help you can provide!

Hi @flashc5
I can’t tell from your screen shot, but in the attached file the flange is just a curve - not surfaces. Try to switch to shaded mode and see. If you want the flange to unroll, ungroup your group (4 times, as you’ve grouped your group several times!) and then explode the rectangular curve. Use Loft to create the four sides of the flange, one at a time. Depending on how to intend to create the flanges (as separate pieces or folded from the sides) you might need to split or create them using the Plane command rather than Loft, but that depends on your deisgn intend.
HTH, Jakob

Hi @flashc5
Here’s how I would do it as a single piece - notice that I’ve used the command UnJoinEdge to dictate exactly what edges are “split” when unrolling. Use ShowEdges to see which edges have been unjoined.
HTH, Jakob
boxflange_JN.3dm (106.9 KB)