this is my model
connecting door.skp (8.4 MB)
rather than trying to work out position / rotation place a door into another like a complete arm contains upper, lower, hand, with fingers containing phalanges
as the main moves, both doors do, then if you reverse rotation and times it by a factor you can achievethe bifold effect with the bottom rotating further than top
connecting door.skp (179.0 KB)
simple and less frustrating formulas,