Surface comparison

Although I’ve been using Rhino for a long time I’m embarrassingly ignorant about a lot of things…
Attached is a file with 5 variations on a surface between 4 curves. The more horizontal curves are pretty simple and the more vertical ones are extracted isocurves and have more points. I’ve used all the surface creation tools I’m aware of that will work for the situation. As you can see the surface structure varies considerably. When you turn on Zebra there are very different results.

I can see that using Sweep2 vertically gives a weird situation with crossed isocurves, (didn’t realize that was possible!), but I’m not sure about the relative merits of the other surfaces. I would be grateful for some advice.
surface comparison.3dm (406.5 KB)

Hi Nick- the simplest surface is not the most straightforward to make but it is noticeably lighter, if that is the goal -

  • MakeUniform the top and bottom curves. They match in points and
    degree but they are not uniform so a loft between them is more dense
    than it needs to be - Loft is a command that likes to have nice
    compatible curves if possible. MakeUniform can make more or less of a
    change to the shapes but in this case it is microscopic, I would say.

  • Loft the two curves.

  • MatchSrf to the vertical edge curves.


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Thanks Pascal,
I had gone with the Patch with 10x10 spans. I guess the shortcoming of that is that it is trimmed? It seemed somehow to be cleaner than the others(?)
I didn’t know about MakeUniform nor that MatchSrf could be used with a curve. Good to know.
Now I have another challenge. I can’t figure out why I can’t Boolean Subract the central polysurface (made from a similar patch) from the two legs. I did the same operation on the other side of the legs and it worked fine. The shape intersects cleanly all the way around as far as I can tell. Boolean.3dm (377.3 KB)
Thanks again.

Hi Nick - the top surfaces make a somewhat messy intersection -

Can you move the two legs up ever so slightly, that would probably be the easiest way out.