Extruding a curve along a spiral

I’ trying to model an involute spring for 3D printing. I started by drawing a spiral and a rectangle. When I try to extrude the rectangle along the spiral I get a distorted shape. I can extrude the two vertical surfaces bit not the horizontal surfaces.

Can anyone explain how to accomplish this?

involute spring.3dm (33.1 KB)

HI Jack - join the lines into a rectangle, I’d say, then Sweep1 with Style=Roadlike Top.
RailRevolve will also do this.


Pascal, THANKS for your reply! I understand sweeping the rectangle 1 rail which is what I tried. I don’t know about “Style=Roadlike Top”. Where can I find info on this. Couldn’t find it in help.


Hi Jack - see


Styles are covered below the initial description.


How do I access the “Roadlike Top” option?

Hi Jack - look in the ‘Style’ dropdown; it’s set to 'Freeform" by default.


where is the styel dropdown? I looked all over my menus nd can’t find it.

When you call the Sweep1 command, you are first asked to select the rail and then the section(s).
After that, you can adjust the seam(s) of the section(s).
When you hit Enter after that, this dialog box pops up:

(unless, of course, if you call the -Sweep1 command (with dash to suppress dialog boxes) - in which case you can access the options on the command line):


Thanks! I was trying to sweep 2 rails and never got that exact option. Showing the options box made a big difference in my pea brain grasping what was presented.

Now I can proceed with the project.

Thanks to all who replied to my query.