Hi TOM,
The two gear reducer profile scripts are poorly named, because they are for generating the rotors for Gear Reducers based upon
either epicycloids or hypocycloids, with an eccentricity. They should be named something like epiGearReducerProfile, and hypoGearReducerProfile.
The mathematics are relatively complex, and come from the cited academic paper.

They do NOT generate epicycloids, nor hypocycloids, although the gear math uses epi's and hypo's as initial math formulas.

So to generate the geometry you show, you should use the hypotrochoid script.
You can look up hypotrochoids on Wikipedia. Hypotrochoids contain hypocycloids, as a subset, when b = d.
(note, the selection window at the upper right for Hypotrochoids may say Epitrochoids, due to my failure to change the options name,
while adapting Epitrochoidscript to Hypotrochoid script.)

The aRadius to bRadius should be 12:2, and the d radius about 5 or 6, and the numcycles = 1.

So I think that your geometry is a hypotrochoid, not a hypocycloid...


- Brian