Constraint linear offset

I have a constraint with limited linear motion. I need to find out how far the constrained object has traveled away from it’s target position. I know how to get the angular offsets(‘Get Current Twist’, ‘Get Current Swing1’…), but I don’t know how to do it for linear offset. Is it possible to do it in UE4?

Physics Constraint API sucks, but you can do it your way:
measure the distance vector between the 2 constrained objects at the beginning of time, and then compare it to the distance at the moment u care about. delta of these two vectors is pretty much the linear offset

p.s. YES I KNOW IT HAVE BEEN 3 YEARS

If anyone finds this Linear offset is basically same as “SetConstraintReferencePosition”. For example my linear limit is 20. and I want draw to start at one end. Here you set it to linear limit /2.