Thank you, Jeff Hammond! It's just what I was looking for!

@mac1 said: Fredo's Curviloft tool seems like a good candidate to me To avoid the small valley, you should skin with 4 contours, not three. The best is to draw small segments in the corners to tell where you wish to cut the contours. Then you can generate the whole shape by preselecting all edges. [image: CbOo_BubbleMac.jpg] One last suggestion: decrease the number of segments of the rounded corners, because it generates a very dense mesh on the borders of the shape. Fredo bubble_mac1 - curvi.skp

Another one can be Soap Skin and Bubble and you will can regulate the pressure +- PS Alas seems now not more accessible for the moment! Time expired for free version! [image: HyperParaboloid.jpg]

how about draw your own plane and use intersect selected?

Without reworking it to draw just four edges rather than make a face_with_its_four_edges, you can recast it to make the face and then erase it immediately - its four edges should get left behind... lines 107 et al... def create_rectangle # check for zero height if( @pts[0] != @pts[3] ) face=Sketchup.active_model.active_entities.add_face @pts face.erase! if face.valid? ### edges will remain... end self.reset end EDIT: CF beat me to it !