I was thinking about my idea in the last few hours.
There are a few more problems that I can't solve right now:
The door moves, that's fine. The ball already has a ramp. (see the picture below) But if I put sphere bounds to the ball it doesn't care about the borders of the ramp and the lock bar, they are static triangle mesh. I move into the room and can see that the ball fell down already, although if the lock bar is still closed.
<<The Ball is green, the ramp (= 4 stacks) are blue and the door is the red object. Usually the ball should stay inside of the stacks.
If I change the ball's bounds to static triangle mesh it doesn't fall down when the door opens. It's still floating in the air, seems to be stucked between the ramp's borders. I have changed the script, the ball should fall down usually.
So it really seems to be the best way to change the ball object's borders to sphere again and to change the script as I did propose.
Let's try to put the ball to a x,y,z-position at the beginning, after click it should fall down by itself, and if we press the button again it disappears (like a hologram or whatever) and returns to it's starting position.
How should the script look like?