Surface from curve network

Hello, I just started using rhino for a while, it might seem a stupid question. I would like to create a chair-shaped surface from several network curve, but I always failed because it says I need at least two curves for a network. Is there any method that I can generate a surface like this from these curves? Thanks!
NETCRVS.3dm (30.3 KB)2eb10ba84bbdebc943b6e5b9142d661f

Not using those curves as they appear there.
Start the command and tap F1 to see the Help file article for NetworkSrf.
It gives clear examples of the kinds of curves that the command is designed to use.

After you’ve followed John’s advice, and assuming that your chair, like most, is symmetrical right to left, you might consider creating the surface using network surface for one half with a half circle at the bottom (but might need another horizontal curve or two higher up to get the shape you want) Then just mirror it around the plane of symmetry to get the other half. If you are careful when designating the symmetry plane for the mirror command to snap to points on the original object you should end up with two halves that can be joined into one object.

Thank you!

Thank you, I will try!

Of course that you can use these curves to build a “Network surface”. You simply have to split the vertical curves with a point where they meet together or using them as cutting objects. Then you can run the “Network surface” command and it will build the desired surface.

You can play with the “Edge curves”, “Interior curves” and “Loose / Position” options for different results.

For example, “Edge curves = 1”, “Interior curves = 1” and “Loose” will build a less accurate, but simpler surface with minimal amount of control points.

If you aim to achieve a more accurate surface that closely follows the input curves, then use “Edge curves = 0,1”, “Interior curves = 0,00001” and “Position”. However, since “Network surface” works with approximation and tries to evenly distribute the control points along the surface, too low numbers (i.e. too many zeros) will result into a huge number of control points.

I suggest to try the other option that may (or may not) give you a more accurate yet cleaner surface - “Sweep 1 rail”. Just use the closed horizontal circle as a rail and the 4 separate vertical curves as profiles, and the “Closed sweep” option. Voila.

And probably the simplest geometry is made with “Loft” (only 25 control points that give you a great control for further adjustment), but this time only use the 4 vertical curves, without the closed one that’s on the ground. I suggest to try the “Tight” style with “Closed loft” and "Do not simplify options. This will force the lofted surface to accurately follow the input curves, but the downside is that the base will be a bit off from the closed curve. However, you can easily fix that by using “Match surface” to match the bottom edge of the lofted surface to the curve. Or simply use manual dragging of the control points.

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Thanks a lot! You saved my life!

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I’m glad to help! :slight_smile: Cheers!

P.S. By the way, if you turn on History recording before you build the surface (be it Loft, Sweep 1 rail or Network surface), then you will be able to easily control its shape by adjusting the control points of the input curves.

Thank you! But now I’m working with this in grasshopper, the sweep1 / loft component can’t work out the desired form as is rhino. Is there any alternatives to create similar form in grasshopper?

you might want to use the merge node instead of entwine and flatten that input going into “sections”