Algodoo

Nice tutorial.
One question. In the last set of gears (on the right) the large gear has teeth that are shaped like a parachute, and the mating smaller gear's teeth are circular. Does the parachute shape have any functional value, such as to improve efficiency, or is it purely for cosmetic appeal?

This is cool but if you scale the inner gear somewhat smaller it dos the same thing and you retain the circle collision vs the totally messed up polygon
collision crap

Xray,

Q: Does the parachute shape have any functional value?
A: Yes, the part of the circle that is removed is the part of the large gear that would interfere with the smaller gear in operation. If it wasn't removed, then the gears would jam.

Gent,
You may be right, show me in a scene where a scaled inner gear outperforms this design. Generally speaking, circles outperform polygons, but it may boil down to the number of collisions that have to be calculated per unit time. If you view normal forces, then you will see that this design generates one collision at a time and that there is little free play between the gear teeth. I'm not sure the same can be said for a scaled down inner circle gear.

You are right and this design runs very smooth
Now if you could make a gear generator similar to
Kilinich's for this type that would be awesome
PS I'm still working on my 3 rotor wankel
minimum # of teeth in the gears seems to be the key
going to take a complete rebuild at this point

just looked at the updated scene YOU are a GENIOUS