I might be onto something, did some research and maybe the correct method for creating such meshing gears would be a Curve Envelope script, that would trace a rolling shape of one curve over the other, in my case a straight rack over a curve arch. The script would work on a "tooling curve" first (here the rack curve) and expect it to be selected first, then selecting the roll path curve. It would expect that the initial position of the two is in its initial meshing position.
The roll path curve is essentially a pitch curve for a spur gear.

That would be all that's needed for production of the Envelope curve. The exact points making the envelope are a result of two parameters, position along rack curve and rack roll progress which drives its position and rotation. The Rack motion just assumes a straight rolling over the pitch roll curve, parallel at contact.

I got the idea from this video https://youtu.be/eG-z-791_ak?t=652

Hi Fubax,

re:
>Now I have an issue, because I want to create a non-circular involute gear,
> and I need to "roll-array" the rack over a curve (arch) with parallel offset to the
> curve to avoid slip at each step. I believe it would be possible with MoI, the
> script would essentially be the "Curve Array" with a roll offset option.

I'm sorry but I'm not understanding what you are trying to do.

How is your ArrayRoll different than circular array?

Do you want the object to rotate in some way on every array step?

Kinda need some more details.

- Michael

I'd look at using something like Gearotic for this. Or at least ask on the Gearotic forum if you want to roll your own.

- Peer