CAD Forum

I am trying to make a helix on a helix and need some help. The example is whipping the end of a rope (brown) with a string (green). I have the rope done satisfactorily. For the whipping I have a single loop loft (shown). As you can see, a linear pattern does not rotate the individual loop with the helix of the rope.

I had seen at one time where someone modeled a garter spring, but have not been able to find it. Perhaps that was on the old forum and those file attachments got 3DSwamped.

I'd prefer the whipping to be a single part, but am okay with patterning multiple segments. I've tried all the patterning options I can think of, but haven't hit upon a solution.

Any help is much appreciated!

Apparently I have to type something here. So check the attached file.

@josh, that is EXACTLY what I want to learn how to do. Unfortunately for me I am on SWX2023. I had to open the file in Onshape to view it.

Would you mind showing me the secret sauce on how you did this?

I am grateful for your help!

Try this one...

@josh, this is it! And thank you for putting it in a version I can use and learn from.

I understand how and why you did the two helical surfaces. I do not understand how you achieved the 3DSketch for the sweep. I had to make a split line from the two surfaces and then make a 3DSketch from that. How did you do it?

The 3D sketch was made using the Intersection Curve command. Just select the two surface bodies and hit Intersection Curve. It will automatically create the 3D sketch and the helical sketch.

If you want to get real fancy you could sweep with twist again...

josh wrote: ↑Wed Jan 15, 2025 8:25 am The 3D sketch was made using the Intersection Curve command. Just select the two surface bodies and hit Intersection Curve. It will automatically create the 3D sketch and the helical sketch.

I had to search for that command: Tools -> Sketch Tools -> Intersection Curve.
This is a feature in an area I rarely explore. I guess this old fart who's been using SWX since the initial '95 version still has some things to learn!

You are awesome with your help, @josh! Many, MANY thanks!

I don't use it often either... I just used the command search box. :-D