How to create a loft that moves behind itself?

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1

Hello,

I’m trying to understand how to create a lofted body that does not just follow guides in a single plane, but also moves smoothly in 3D space.

What I’m trying to build is an S-shaped curve network where the tail passes behind the lower part of the same letter and then continues into the next letter.

What works so far:
A single loft works well as long as the shape stays in one plane. By adding a few construction planes along the path, I can get the “swirling band” effect I want.

Where I get stuck:
As soon as I try to move the shape behind itself in another dimension, the loft stops behaving as expected. I tried adding another guide to control that movement, but the loft does not seem to follow that path correctly.

What I tried as a workaround:
I split the shape into multiple lofts and use an additional loft to create the bend. That gets me closer, but it creates a sharp edge where the lofts meet.

I also tried using Start/End Continuity settings to smooth out those transitions, but that fails as well.

So my main questions are:

  • Can Loft in Shapr3D handle this kind of 3D path reliably?
  • Is there a recommended way to build a shape that moves both sideways and backward/downward in space?
  • Should this be done as multiple lofts, with sweep used for the bend, or in some other way?
  • What is actually required for G1/G2 continuity to work in this type of loft?

I’ve attached a simplified test video that shows the problem more clearly.

Any guidance would be appreciated.

2

Not sure I replicated your geometry exactly, but it looks like it isn’t impossible.

image
image1920×1080 110 KB

Can you share the project where you’re having problems?

3

Oh looks you were able to make it work?

Here’s my test project, it’s not the actual shape of the real project, but I have the same issue when I have this bend and try to add a dimension the same way as this

shapr3d_export_2026-04-02_16h11m.shapr (20.4 KB)

4

The problem is quite obvious, the second part of the guideline is not tangent to the first one.

5

Sorry for my beginner ignorance, I assumed it would be enough to connect them on the intersecting points. How do you make them tangent when they are different sketches on different planes?

6

Well, this kind of thing should be done from the beginning, but for learning purposes I’m showing how to correct existing geometry.

Not a tutorial — just recording my actions on the go, so some steps aren’t really necessary. :slight_smile:

7

Thank you so much!

I spent many hours trying to figure this out, now it makes sense why it didn’t work! :tada:

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