Rotating wheel with rigid body dynamics

Question

In my scene I have a wheel shaped cylinder with rigid body dynamics attached to it. I also have a floor with passive rigid body dynamics. Now what I want to achieve is to have the wheel spinning while it falls down to the plane, to then get grip and roll off the plane. I already tried these three scenarios.

1. Rotating the wheel using an animation. In this scenario the animation doesn't play anymore once the dynamics kicks in. Checking the "Animated" option in the rigid body settings eliminates the gravity effect.

2. Using a shape key to rotate the wheel. This doesn't work either because the shape keys deform the object in the transition.

3. Using bones but this gives the exact same result as using animation.

I'm sure there is a ways so I am curious to hear your suggestions.

UPDATE:

Animating the "Animated" checkbox works partly. So the "How can I add motion to an object" does not work as I tried it already earlier. Rotation is lost eventually and I need it to work like a motor.

Answer 1

In the rigid body world there is a rigid body constraint 'motor', this is assigned between two rigid bodies.

What you need is:

1. The original wheel - active rigid body
2. An object to push on (a simple cube) - passive rigid body - constrained to the original wheel (hidden inside for example)
3. An empty - rigid body motor constraint: angular motor - also constrained to the original wheel

Now the wheel is motorised and will drive itself across the ground plane.

Hope this helps!