# How can I calculate the coordinates of segments that form a hanging chain?

I'm trying to get a chain physics model with segments. I'm feeling rather stupid, but how can I calculate which is the new position of each dot when the chain moves its ends?

expressed in another way and considering just three segments of the same length: which is the way for automatically calculating the different P1, P2. when an end moves?

• Create a free body diagram for each segment? This should give you a set of simultaneous equations for the $x$ and $y$ components of the forces acting on each dot. – Gert Mar 18 at 11:08
• You may find my answer here helpful: physics.stackexchange.com/a/421965/123208 – PM 2Ring Mar 18 at 11:26
• @PM2Ring I did see it, however i cannot understand how to get the equilibrium in the formulas of your answer. But that's exactly what I want. – galtor Mar 18 at 11:32
• Sorry, but I don't know how to explain it better than what I said in that answer. But if you'd like to know how to calculate the points on a chain given its length and the coordinates of its end points see the comments at the start of my old POV-Ray code here Also see here. – PM 2Ring Mar 18 at 11:59
• Thanks for the reply, @PM2Ring. What I cannot understand is how you fix the two ends. In your drawing, P0 is the lowest point, and the rest of coordinates come from it, isnt? – galtor Mar 18 at 12:47