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Hi dreamers!

I have been confused about scaling a moveable object using a keyframe.

I am trying to make a sphere smaller as it rolls along. To do this, I do the following:
1. Use a rotation sensor to get the overall angular velocity;
2. Put its output through a signal manipulator to clamp an angular velocity of 10m/s to an output of 1;
3. Put this output into a timer set to "speed", so that the ball will get smaller quicker when it rolls faster;
4. This output is then put into the keyframe, which is the scaled down sphere.

Here's where the trouble starts. When using a keyframe to scale the object down, all kinds of weird stuff happen. To avoid scaling on a global scale, I group the keyframe with my sphere. But if I animate it like this, the object is no longer moveable once it starts rolling. On a timeline, it is only moveable again after the scaling animation is completed, but I want the sphere to be moveable during the animation.

Finally, I tried John Beech's method of grouping an invisible sculpt with the sphere, animating the sphere in the group, then make the group moveable, not the sphere. This however makes the sphere bound to the physics of the other object. The invisible object will hit other objects, resulting in strange movement behaviour of the sphere as it is dragged along. Finally, I tried to make the invisible object non-collidable, but then the invisible object pulls the sphere through the ground as it is forced to move along with the invisible object.

I really am kind of lost here, so any input would be much appreciated!