Internal Cycloidal Drive Gears tutorial for Fusion360, This type of gear stands out because it allows a high reduction like the standard cycloidal gear, but the design process is much much simpler.

this model is an inversion of the external gear I made [https://www.printables.com/model/818861-cycloidal-gears-tutorial](https://www.printables.com/model/818861-cycloidal-gears-tutorial)