trampoline up and down issue


i would like to create a trampoline effect, with the shape keys, a driver and a bone. It works fine if the trampoline only goes up, or down, but if i add both shape keys at the same time, the bone/driver does not understand and plays the two effects together (it goes up and down at the same time, when i move the bone in the Y location axis, so the effect does not work).

Is there a way to create this bouncing effect? I wanted to start with a plain surface, then the trampoline goes down, and goes up, bounces a little like that, and comes back to its original plain shape.

Any idea?


You can try either of these.

Remove the down shape key and set the Range value for the up shape key to -1.000 min.

Create another driver and set both of the shape keys to a separate driver. For the down driver, set the expression to -var, and for the up driver, set it to var.

Thanks, okay i think i will keep only one driver, as your first suggestion, because i cannot really make it work with two, what does “var” stand for here? and the thing with y in -1 or 1, i am not sure to understand, so i’ll keep it simple :wink:



var is the default name of the variable in the the driver properties. You’re looking at the wrong thing, you only need to change the expression itself at Expr: 0.000 (default) to var, or -var. The modifier you’re looking at is used to change the driver curve itself. Anyway, if it worked with one driver you don’t have to use two. :stuck_out_tongue:

okay, thanks!