retractable rods?

#1

Basically, ive got to animate some retractable devices, with movement much like that of a telescope, with rods within rods all moving out and in together.

Im new to writing expressions for translate position, and was wondering if someone could help me out with creating some useful constraints so that the whole piece will move out with the ‘head’ piece.

The poles need to only move when the ‘head’ piece is far enough away, and then, also only move back when its close enough. Dont really know if im articulating this very well, but a telescopic/rectractable antenna is the closest reference i can give.

Cast some light on this for me.

  • Cheers
#2

i dont know what software you are using, so im just going to write pseudo code

telescoping rig consists of 3 cylindrical objects large, med, small. all have pivot points centered together, all pivots are tY = 0

assuming you want to animate the small object and have the others move with it when it becomes far enough out

small’s tY would be controlled by you

medium’s tY would have this expression:
if(small.tY > lengthOfMedium)
then medium.tY = small.tY - lengthOfMedium

large’s tY would have this expression:
if(medium.tY > lengthOfLarge)
then large.tY = medium.tY - lengthOfLarge

and so on and so forth, for however many objects make up this telescoping thing

#3

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