Check the attached 3d model in Rhino 7 file format. While trying to build a patch surface along the cyan and aquamarine arcs, I noticed that using 5 or more spans will result into a random shape that changes drastically depending on the stiffness or number of spans. The “Patch” toll should perform better in this very simple scenario where the input curves are two basic arcs, but for some reason it fails.
On a side note, is there a tool in Rhino that will build a clean double curved geometry from two crossed curves like those two arcs? Other CAD programs have such a useful tool.
For example, “Sweep 1 rail” will ignore one side of the arc and will build a half surface instead. If I build two surfaces on either side and then merge them together and remove the knot in the middle, I can get an approximation of the two crossed arcs, but that surface will not be accurate and will have more control points than necessary. It can be seen by the end of the video.
“Patch” with 1 span at either direction somewhat builds a simplified surface, but it’s not fully accurate and still does not follow the two input arcs precisely. Also, it extends the surface beyond the size of the arcs.
Cheers,
Bobi
Crazy Patch shape.3dm (118.8 KB)
This works just as intended. Looks like this is sort of a “Revolve” tool that uses the normal direction of the arc as an axis. Can it be history enabled in the future? I think that this script must be a native modeling tool in Rhino. I just added it as a right-click of the “Sweep 1 rail” icon.