# Cut Out a Helix from a 3D Object

I want to cut out a helix from an asymmetrical 3D object, like this:

I know how to create both a uniform and a tapered helix, using either native tools or plugins. However, I can’t figure out how to create one when the shape is neither uniform or tapered.

Cheers

Mark

This is a simpler version of what you show.

I drew an ovoid with Follow Me using a Bezier curve as the profile and a circle for the path. I made the ovoid a component and then outside the component I drew the helical curve around it with the Line tool drawing between corners of the faces. Turning on Hidden Geometry helps.

You only need to draw one helix because it can then be copied with the Rotate tool to make the second one. Cut the helices to the clipboard, open the component for editing and use Paste in place. Then select the surface that you don’t want to keep and hit Delete.

I used 96 segments for the Bezier curve and 48 for the number of sides in the circular path so I only have two turns. In your illustration it looks like there are 6-1/2 turns so you would need 6.5 times as many segments in the profile curve as in the path.

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Is it all ready egg time of the year?

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Thanks DaveR,

I’ve followed your instructions and it works a treat.

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I created a helical ribbon as per DaveR’s instructions.

I wanted to give it a thickness, which I did using the “JointPushPull” extension from SketchUcation:

As a learning exercise, I was wondering:

• are there any alternative methods?
• can it be done with native tools?

Cheers

Mark

I think using Joint Push/Pull was the most expedient route.

You could do it with native tools. When I made my egg shape, I had a sort of D-shaped profile for Follow Me. You could make it C shaped so you wind up with an inner and outer surface to the shell. Then you could draw the helices on the inner and outer eggs, create the ribbons as on the single egg and finally stitch the edges of the ribbons together with the Line tool. It’s probably a good exercise and it would help you learn more about the modeling process and what it takes to create the faces. It’ll also make you appreciate tools like those of Fredo6 a whole lot more.

Thanks again, DaveR