animated gears

Just wondering if anyone can help me with getting a set of animated gears to work properly. I need them to be able to rotate in opposite directions, and at the right speed(one is three times the size of the other). I think i’ve got the right numbers of teeth for them to mesh, but i cant figure out how to get them rotating in sync. Thanks for your help

Something like this?

http://mysite.iptic.com/s68/movies/gears.avi

(DivX 5.0.2, 2.2 Mb)

It is not as you may think, you cannot make one weel rotate and the other follows.

You must set rotation of each weel separately, with correct speeds, calculated via good old mechanics laws.

Roughly

Angular_speed_wheel_2 = - Radius_Wheel_1 * Angular_speed_wheel_1 / Radius_Wheel_2

but the ‘radius’ is itself to be defined. it is the base line of the gear teeth, and teeth protudes beyond the base line as circular evolvents and beneath too, if you don’t get the curves right you’ll get weels getting one inside the other…

Good luck

Stefano

Try this blender file http://www.garyowen.eurobell.co.uk/blender/gears.zip

You will need to have Python 2.0.1 installed as it uses procedural animation.

Simply place your cursor in the main window and hit Alt+A.

Wow. Just in time. Just got an anim to do of revolving gears for the Met Office. Blender never ceases to amaze me.
Thanks Gowen

Cheers