I'm really confused on what joint to use for my system. I'm making a hand with fingers that move. I need joints for the knuckles of the fingers. I plan to move the fingers using Inverse Kinetics(IK). Unfortunately the new joint system of attachments and constraints is broken(thanks roblox), and the old system is confusing to me. What joint from the old system should I use?(motor, weld, ect.)
You can make a Motor6D and set its Part1 and Part0 and all that ( assuming you know how to work with welds )
local m6d = Instance.new("Motor6D", path.to.something)
To read more about Motor6D here is a nice wiki page: http://wiki.roblox.com/index.php?title=API:Class/Motor6D