Why does this cube slide backwards? (Rigid body, rotation, physics)

Hi there,
i’m trying to do some mechanical movements using game engine and rigid bodies. However, I have a rough start, for example this cube rotates forward but if I start the game engine, it slides the other direction similar to michael jacksons moonwalk.

I couldnt find the solution myself, friction nor mass do the trick. Does anyone have an idea what could be wrong? I’m working with Blender 2.69 on mac.
Thanks for your help,

TestANiGAmeA.blend (836 KB)

There’s nothing wrong with the action. But the motion is simply the result of the cube rotating in one direction. You could check this by holding a stick in your hand and letting it go while giving it a spin to the right. On impact it will bounce to the left instead because of the counter force.

It seems awkward, why? Because we are not used to see cubes rotating “on their own” and unconditionally (nothing will prevent the rotation from happening). What we are used to see is cubes that rotate because they are thrown or pushed at the corners.

Activate “force” in the Action Actuator. Then it will move as expected.

What is your aim? What do you want to achieve?

Thank you very much, your explenation makes sense. Never thought about that. Also I will try it with “force” on.
Well, I have no specific goal just yet. I’m an artist (fine art) and just very interested in mechanical mobiles and their behaviour in virtual spaces. Its more like a research right now, maybe eventualy some kind of artwork will spawn out of it :wink: