Convert spline to revision cloud

i have a lisp convert spline to revision cloud. but i want convert with any length ( ex.1000mm...or etc with min arc length = max arc length ). can you help me ?

(defun c:51() (command "revcloud" "A" 200 500 "") (princ))

Thanks all.

(defun c:Test (/ ss)
 (if
   (setq ss
          (ssget "_:L" '((0 . "SPLINE")))
   )
   (
     (lambda (i / sset)
       (while
         (setq sset
                (ssname ss
                        (setq i (1+ i)
                        )
                )
         )
          (command "_.revcloud" "_A" 200. 500. "" sset "")
       )
     )
      -1
    )
    (princ)
 )
 (princ)
)

Tharwat