3rd part of my involute gear series, about contact ratio.
Animation manim sources:
https://github.com/GarryBGoode/Involute_gear_video_sources_2_3
Gear drawing toolbox for manim:
https://github.com/GarryBGoode/manim-GearBox
CAD utils for manim for dimension drawing:
https://github.com/GarryBGoode/Manim_CAD_Drawing_utils