Hit a snag with Rhino 6 level 2 training material

Yes, I created the top turtle like surface using ‘patch’ command/tool David. And, let me ask you… when you extract a surface, like a copy I guess, then afterwards use the untrim tool… then, like will it just look the same or extended after untriming an extracted surface? I know with a original surface, it will look different, as in extended beyond the trim/edge (way beyond).

B.T.W. I got the bottom sealed by using ‘Surface from 2, 3, or 4 edge curves’ tool. I hope it’s perfectly flat… I zoomed in and it sure looks that way at least. :+1:Trackball19.3dm (919.7 KB)