`(defun Paral3D (obj1 obj2 / a1 a2 acos)`

(setq a1 (vlax-curve-getFirstDeriv obj1 0)

a2 (vlax-curve-getFirstDeriv obj2 0)

acos (/ (apply '+ (mapcar '* a1 a2))

(* (sqrt (apply '+ (mapcar 'expt a1 '(2 2 2))))

(sqrt (apply '+ (mapcar 'expt a2 '(2 2 2))))

)

)

)

(zerop (atan (/ (sqrt (- 1. (* acos acos))) acos)))

)

Alan,

While this is interesting, do you think there's any reason to revise MinDist 1.0 to use it?

I think not assuming it is only testing for parallel lines.