I got a model from someone. It was spur gear model.Relations were used in it.It was total calculation including addendum, deddundam kind of thing.
In that model the gear curves were created through equation.I didn't get the equation but knew little about the relations.
How to create curve through equation?
That model comes from a gear company: https://sdp-si.com/
You can download their 3D models in Pro/E format and see how they use those involute curves.
This is one I downloaded... they are definitely beyond what I want to tackle on the fly: