Hello everyone,
I've used the classic 2DGEAR.LSP AutoLisp program numerous times over the years, and have made some improvements to it for my own needs that I think will be useful to others. They are as follows:
Generation of internal gears (i.e. a gear whose teeth point inward instead of outward) is the main new feature; I was needing this for a personal project and there didn't appear to be any good options outside of expensive engineering applications. It turns out that the profile of an internal gear is really just a variation on the profile of a regular external gear, so some tweaks to the addendum/dedendum are all that were needed for 2DGEAR to gain this ability.
An external gear that only meshes with an internal gear is a special case that I also added. This one can have a smaller dedendum, meaning the teeth are not as deep/long, and are thus stronger---which is nice if your application involves a lot of torque.
And the elaborated documentation will hopefully help those who wonder why a simple gear-generator program has so many options!
Comments and feedback will be appreciated. This work could certainly use a once-over from a gear guru, if any are reading this forum...