Cannot Seem to Make Threads with Grasshopper's Sweep1

I am trying making a threadcutter to remove material for threads.
I have a nice spiral.
I have a profile curve.

The resultant sweep not only goes off the rail, but it twists, as well.
I tried adding more profiles, but that didn’t work either.

I might try making a high and lower spiral and try sweep2, but I am not optimistic.

No, Sweep2 did not do exactly what I wanted. I check the endpoints, to make sure everything starts where it’s supposed to.

I tried a single surface, but it twists that too. I think that what it needed was “Roadlike top,” but it doesn’t have that.

This is the result for a single surface.

I feel that if i put a whole bunch of intermediate curves in there–the result will have tension and twist where it’s not supposed to.

share your file if you want help

Without something akin to roadlike-top, there might be a reasonable solution.

While there is some powerful and sophisticated tools in Grasshopper, there are some missing basic functionality.

I encourage you to make some threads, using the missing spiral tool, and see how it works out with the missing road-like top.

File would help

Sweep2 seems to cut it ok:

helical thread (29.8 KB)


Jeremy, will it work with root and crest?

Hi Brenda,

Sorry, you’ll need to explain what you mean by root and crest - I’m not a thread expert :wink:


But here’s a version of the demo which is done with a proper metric thread profile (a 36x4 male thread):

I have added some notes to the grasshopper file:

helical thread demo (40.9 KB)

But I’d stress that this is just a demo of how sweep2 can work OK in grasshopper for this. It isn’t a tool for generating threads (although it could be a starting point for one).


For ,the recors, here an old discussion on thread


Great resource, thanks Laurent.


I made a functional thread using the grasshopper tools with a 3d print in sand. There is a bit of friction but it works very well. As it is a bulb holder, it hasn’t to be opened and closed very often.

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