Problem creating surface

[tianci]

Hello everyone

I want to create a smooth untrimmed surface using three curves. Is there any way? Or an open brep will also work. I tried to create it but the brep I got always overlapped. I hope you can help me. Thanks in advance.

Tianci

problem creating surface.3dm (824.7 KB)

[martinsiegrist]

I think I would take just a quarter of the curves and instead of sweeping I’d create a tween curve, scale it and then loft the three segments. Then mirror twice, join and cap if necessary.

problem creating surface.3dm (2.2 MB)

[Toni_Osterlund]

@tianci
You can create an untrimmed surface instead of a polysrf, if you remove the sharp corners with i.e. 1mm fillet.

(the top curve was flipped)
SweepSrf.gh (18.4 KB)

[Joseph_Oster]

@wim

Heads-up, this is a duplicate from

Great. After I’ve already done the work. Why weren’t they merged or the duplicate purged?

brep_from 2crvs_2023Sep15a.gh (27.8 KB)

Curves are internalized, no need for Rhino file.

P.S. Now I see that the 3rd curve connecting the other two is not a straight line.
What a waste of time!

[martinsiegrist]

Yeah but this leads to a ton of self intersections…

[Joseph_Oster]

brep_from 3crvs_2023Sep15a.gh (19.8 KB)

[martinsiegrist]

Hmmm, this also creates self intersections.

[the_eraser]

Brilliant!

[davidcockey]

@tianci

I want to create a smooth untrimmed surface using three curves. Is there any way?

Because the lower curve has kinks any surface which fits it will also have kinks and not be smooth. It can be a single surface with full multiknots at the kinks, or a polysurface.

[lander (CAD CAM CNC)]

problem creating surface_emod.3dm (7.0 MB)

guess I rounded some corners …

sharper version:

problem creating surface_emod_sharper.3dm (8.7 MB)

The incorporation of the mirrored symmetry would be a trick near the end of the workflow of course.

Still not sure what the design intent is or if GH is a requisite