Create a Scalloped Rack Gear Edge

I need to create a rack gear edge on surfaces. This illustration shows the profile I need on top of one of the surfaces.

In this case wirecut or extrude and subtract would do it. However, I have edges of various shapes that need a gear edge cut into them. I have found several gear solutions to straight edges but none for curves.

Any ideas on how to approach this?

Hi @miano,

You can create a straight rack profile and use Flow along Curve (_Flow) to fit it to a different shape:

  1. Create a straight rack profile
  2. Get the length of the target curve and create a straight line of that length along the profile.
  3. Use _Flow with the straight line as the baseline and the curve as the target.
    (experiment with the _Flow options to see what suits your purpose best - a lot depends on what distortion you can accept.

The help file entry on Flow along Curve will help with your choice of options.


Thanks, I have been able to do some of the curves so far. Still struggling with others.

I have gotten this to work on the flat surfaces but am having problems on the curved. Any ideas how to make radial cut?

Problem (538.3 KB)


1Flow_.3dm (2.3 MB)

What wirecut settings did you use? Have not been able to get wirecut to work at all?

What I did get to work was to straighten the polysrf, cutout the gears, then use flow to curve the polysrf back to its original shape.

just set the direction in X and then drag in -y

The edges get more complex for this problem. How might I approach this:

I have a truncated cone (in blue) The upper truncation is curved. Using FLOW as suggested I have created a scalloped edge at the top (you can ignored the inner shape).
Now I need to create a scallop shape that lies along the cone with the teeth going down.

The shape I need to create is then a cone with the bottom edge scalloped.

In in the real word, the outward scallop and the downward scallop would be an L-Bar wrapped around the cone with teeth cut into it.

(I also need to create similar scalloped L at the bottom.)

Hi @miano - Take a look at the two clips attached. Does this help?

Flow - Top Crv Flow - SIde Crv

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