thx dannyngan, found it, but i would like to avoid to script the whole sequence..i try to stick with only expressions, if its possible. maybe my whole concept is wrong, how could i do the following example:

-barrel rolling to one direction, than turns 30deg, and continues rolling along the new angle. expression calculates the roll and wobble of the barrel shape. no path. how should i do it?

as i add a parent, the channel controls use local axis ,but rotation after child transformation wont be correct, of course.

i feel its too simple, i miss something..

thx