How to create a 3D shape connecting two square curves along 2 other curves?

I want to connect both 'squares so that they follow the two curves on the X-Y plane. I tried playing with Sweep2, Loft, and other Surface tools but I couldn’t get it. I’m new to Rhino so I’m still not that familiar with everything.

Once that’s settles, I want to UnRollSrf of the shape, but will I be able to since it’s a ‘deformed’ shape? If not, is there another way I can UnRoll the shape? Because I then need to apply a pattern to it and then re-form the shape.

Thanks you!

Hi Amanda - Sweep2 should do it, I’d think, with the two curvy curves as the rails - can you post your curves? If you want a solid, Cap the results from Sweep2.
UnrollSrf may or may not work on the result - it is very liklely not developable, but lets get the shape made first.

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I selected this as my first rail but it wont allow me to click on the other curve as my second rail…? I tried earlier today and it worked but it gave be a weird distorted shape, it didn’t follow the path properly.

Hi Amanda - there is really little I can do to help unless you post a file with your curves in it so I can have a try - look above the text when you respond or edit your post - click on this thing:


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3D shape pavillion.3dm (30.6 KB)

Hi Amanda -

  • somehow one of the rails has been turned into a control object - select both and Explode.
  • Join the four sided shapes into single closed curves.
  • use the ‘Maintain height’ setting in the Sweep2 dialog.

How’s that?

Btw, Cap will not work to close the object as the openings are not planar. But ‘EdgeSrf’ on the four edges there, in this case, followed by Join should do it, if you need a closed thing.

And, UnrollSrf does work on the object to get the flat patterns.


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3D shape pavillion.3dm (109.3 KB)

Yes, the sweep worked, except the edges are rounded for some reason, is there a way of returning the edges so they are straight? I think this might have somehting to do with Fillet and the Radius, but I don’t know how to change it. When I checked maintain height, it didn’t change anything as if it was unchecked. And what does it mean when creating the sweep and it asks in the command bar, “Drag seam point to adjust. Press Enter when done. (Flip, Automatic, Natural)”, and it shows a light grey arrow on the object?

Thank you for your help, I really appreciate it!

Hi Amanda - make sure to look at Help for this command - it has a lot of options. Your shape is softened because you used the Rebuild option in the dialog - use ‘Do not simplify’. The seam point must be set on commands that connect closed input curves so that Rhino knows where to consider and line up the curves’ start/end points - if these so not line up and point in the same direction you’l get twists in the output. It looks like Rhino guess right in this case so you do not, at least here, need to adjust the seams - Enter to accept.


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Awesome, thank you so much!! :slight_smile: