I s support for generating a plane spiral planned?

jeffery_biss697

I need to generate a plane spiral to act as a guide curve and don't see that it can be done, "spiral" is not in the tools nor is a result in Help. Is support planned?

andrew_troup

jeffery_biss697
Arithmetic or Logarithmic?


At the moment, probably the closest way is via a pseudo-spiral, a chain of semicircular tangent arcs (or quarter-circle, eighth-circle etc, providing successively closer approximation)

You will probably get an answer as to whether plane spirals are on the list for implementation, but you are unlikely to get any timeline from the developers: Onshape features generally get released when they are considered to be "done" rather than according to when the schedule considers they should have been done. What you can do is submit an Improvement Request for users to vote on: items receiving lots of votes tend to get earlier priority.

kevin_o_toole_1

For a perfect Archemedean Spiral, you can project a conical helix into a sketch.

Example:
https://cad.onshape.com/documents/c526017c3b894f329b22c776/w/a189b5aba46e4e78a5fa6ecd/e/9474fe11c7f540f4a5752185

ilya_baran

Creating a real Archimedean spiral is not too hard: https://cad.onshape.com/documents/c7635269c92d41b8ae8f42e7
That doesn't mean that we wouldn't want "native" sketch support for them where you can constrain it and say dimension the pitch etc., but this is a workaround.
Logarithmic plane spirals are harder -- not sure how to do them other than what Andrew suggested above...

andrew_troup

jeffery_biss697
Arithmetic or Logarithmic?


At the moment, probably the closest way is via a pseudo-spiral, a chain of semicircular tangent arcs (or quarter-circle, eighth-circle etc, providing successively closer approximation)

You will probably get an answer as to whether plane spirals are on the list for implementation, but you are unlikely to get any timeline from the developers: Onshape features generally get released when they are considered to be "done" rather than according to when the schedule considers they should have been done. What you can do is submit an Improvement Request for users to vote on: items receiving lots of votes tend to get earlier priority.

kevin_o_toole_1

For a perfect Archemedean Spiral, you can project a conical helix into a sketch.

Example:
https://cad.onshape.com/documents/c526017c3b894f329b22c776/w/a189b5aba46e4e78a5fa6ecd/e/9474fe11c7f540f4a5752185

ilya_baran

Creating a real Archimedean spiral is not too hard: https://cad.onshape.com/documents/c7635269c92d41b8ae8f42e7
That doesn't mean that we wouldn't want "native" sketch support for them where you can constrain it and say dimension the pitch etc., but this is a workaround.
Logarithmic plane spirals are harder -- not sure how to do them other than what Andrew suggested above...

ilya_baran

Ok, Kevin, you win this one!

Narayan_K

@ kevin_o_toole_1  Thank you.Nice work around.

andrew_troup

In search of the elusive Logarithmic Plane Spiral ....

Of course I just had to try a revolved spline in lieu of a cone, in
kevin_o_toole_1's model -
but when "Help" says a helix can only be created on a cylinder or a cone, it's telling the whole truth  
(Just thought I'd save everyone else the trouble) 

So I contrived a workaround to allow me to create an intersection curve between an Archimedean helix and a witch's hat (revolved spline) .... but I hadn't thought it through properly. I never completed it, because I would clearly have achieved nothing whatsoever. As this graphic should explain (Doh!)

pete_yodis

You could very well approximate a "golden spiral" all within a sketch using a series of golden rectangles as the common intersection points for the arcs that would comprise the composite spiral...

https://en.wikipedia.org/wiki/Golden_spiral
https://www.youtube.com/watch?v=_eTw5lKKzmk

jeffery_biss697

Thanks to all. As ilya_baran notes, I was wondering if a "native" means is in the works. Until then, the solution is to produce a spiral "from scratch".

MichaelPascoe

I realize this is an old post, but if you ever need a solid body spiral try this feature out: Spiral

alnis

You can also use the parametric curve featurescript with the cylindrical function type to make any sort of spiral you want, as long as you can write a parametric equation for it. Example:
https://cad.onshape.com/documents/1608b80541c591177445d86b/w/89574a510d51bbc2d5d2e8ca/e/9816ca6829ca7ef8f8c64561

joshua_wang105

If anyone still wants it, this featurescript creates a logarithmic spiral on a plane/cone given start/end points, an axis, and the angle of the spiral. https://cad.onshape.com/documents/35ce4857e66d36eb3f37c90f/w/4c85552a1663ecb0da8fedab/e/df1be8a1e7cafb0bcda34adb