Loft only gives me “Straight sections”

Rhino
1

Hello everyone,

I’m modeling a stainless steel sculpture for real-world fabrication (cutting, welding and assembly).

I have a set of open 3D curves that define one of the “ribbons” / arms of the sculpture, as shown in the reference image I attached.

The ends of this piece are already solved correctly using Loft, and Rhino generated clean surfaces there. The rest of the sculpture is also working well.

The problem is only with this middle section.

When I select the curves in order and run Loft, Rhino only gives me the “Straight sections” option, and the resulting surface is distorted and very different from the clean, smooth shape of the reference sculpture.

I have already tried:

  • Rebuilding the curves with the same number of control points
  • Patch
  • Different Loft styles/options

But I still cannot get a clean and continuous surface without wrinkles or unwanted deformation.

What would be the correct Rhino workflow to create a clean surface from these 3D curves?

Would NetworkSrf, Sweep2, another Loft setup, or a different approach be more appropriate?

The final model will be used for actual stainless steel sheet fabrication, so I need the surface to be clean and properly controlled.

I have attached screenshots showing the curves, the resulting Loft surface, and the reference sculpture.

Any advice would be greatly appreciated. I’m still learning Rhino, so if there is a better way to construct this type of surface from the beginning, I’d also be happy to learn it.

Thank you very much!

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2

Hi @Pablo_Justo can you send the 3d model or part of the model that you have issue with?

3

Hi @Gijs, yes of course, thank you!

CRICULO YA HECHO.3dm (3.2 MB)

4

I think you should approach the red shape in a similar way you did the green. Looking at the image, the red shape is in fact composed of two elements that cross each other.

5

Thank you very much, Gijs. I need to do it as it is in MESH, in the layer labelled ‘bruto a’. I’m quite a beginner and didn’t understand how I should go about it. Is there a command I can use to do a ‘_loft’ to create the surface with the curves I have? Thank you very much again for your help.

6

I’d still build them from two shapes. Maybe lofting square shapes (draw a spine curve, then Cplane to curve, draw a rectangle, array along curve (ArrayCrv), then Loft with History enabled, followed by tweaking the lofted shapes:

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lofted-sections-with-history.3dm (2.5 MB)