Rigid Body - "Motor" Constraint

Does anyone know how to actually use this constraint?
The name speaks for itself and I need to use it but can’t seem to figure out how to get it to work on a simple box cart with 4 wheels.
Any help would be greatly appreciated.

The motor constraint is in a somewhat experimental state. It’s hard to use since there is no visualization.
This will improve in future versions.

I can’t write a detailed tutorial atm, but here is a example file you can play with: http://www.pasteall.org/blend/21275

Thanks, I just realized it has to be used in conjunction with a hinge in order to work.
Took a bit of playing with but I think I understand the basics enough to tinker with it.
Very cool work. Thanks.


I have downloaded your example file and I am playing with the motor constraint.
A question: is it possible to detect the collision of a RB-Object(with a motor constraint) with a passiv RB-Object and then invert the “Target velocity” ?


I entered mortal combat with the Motor constraint this weekend. The biggest gotcha is that the motor uses the X axis of the constraint Empty, and the hinge uses the Z axis of its constraint Empty.

Jasonhan is not entirely correct. A motor can be used without a hinge (I have a video of this on my “notechsupport” youtube channel, the physics demo). But if you want things to not be crazy, you’ll probably want a hinge. Just remember the axis difference between the two constraints and rotate one of the empties to align the two different axes.

If there is a video that does a better job of explaining things than the one I made this weekend, I’d like to know. Maybe I should just dive in and start editing the documentation wiki :confused: