i have 1 top level assembly. inside this assembly i have 2 parts, and 2 subassemblies. inside the first subassembly, i have 2 parts. inside the second subassembly i have 1 part and one more sub-subassembly. inside that sub-subassembly, i have one more part. each of these parts all have a "height" and these heights will always be the same. how do i set up a parameter called height so that when i change it, all of the parts within subassemblies all the way down all change even if they arent in the top level assembly. global variables cannot do this. what is the cure, help