Change view to based on two points -Lisp

;;; This routine will dview twist a drawing by
;;; selecting points in the drawing.
;;; Also sets the snap angle for the new twist.

(defun C:DVT()
   (prompt "Select Points From Left To Right.")
   (setq point1 (getpoint "\nSelect First Reference Point:"))
   (setq point2 (getpoint "\nSelect Second Reference Point:"))
   (setq ang1 (angle point1 point2))(print ang1)
   (setq new_dv (angtos (- (* 2.00 pi) ang1) 0))
   (command "_dview" "" "tw" new_dv "")
;;; (setvar "snapang" (* -1.0 (getvar "viewtwist")))
   (princ)
)