I am trying to make a model of a chain that is anchored at both ends and has moving parts which stay the same length and rotate around each other in the center. How can I make both end points stationary while allowing the middle parts to move in relation to each other?
Anything from manual animation to expressions to simulation with Newton 2. This is nothing that trivial if it needs to be real. Otherwise you can always fake it with effects like Bezier Warp or the legacy Path Text effect.