;; | ---------------------------------------------------------------------------
;; | GE_Extents
;; | ---------------------------------------------------------------------------
;; | Function : Return the x,y and z extents of a list of points
;; | Argument : 'vlist' - List of points
;; | Returns  : A list of p1 and p2, where p1 is lower left corner point (x,y,z)
;; |            and p2 is the upper right corner point (x,y,z).
;; | Update   : March 6, 1998
;; | e-mail   : rakesh.rao@4d-technologies.com
;; | Web      : www.4d-technologies.com
;; | ---------------------------------------------------------------------------

; Return the Extents of a list of points.

(defun GE_Extents(vlist / MinX MaxX MinY MaxY MinZ MaxZ tmp pt )

(setq
	MinX 1E20 MinY 1E20 MinZ 1E20
	MaxX -1E20 MaxY -1E20 MaxZ -1E20
)
(foreach pt vlist
	(if (< (setq tmp (car pt)) MinX)
        (setq MinX tmp)
    )
    (if (< (setq tmp (cadr pt)) MinY)
		(setq MinY tmp)
    )
	(if (> (setq tmp (car pt)) MaxX)
        (setq MaxX tmp)
    )
    (if (> (setq tmp (cadr pt)) MaxY)
		(setq MaxY tmp)
    )
    (if (and (setq tmp (caddr pt)) (< tmp MinZ))
		(setq MinZ tmp)
    )
    (if (and (setq tmp (caddr pt)) (> tmp MaxZ))
		(setq MaxZ tmp)
    )
)

(if (= MinZ 1E20) (setq MinZ 0.0))
(if (= MaxZ -1E20) (setq MaxZ 0.0))

(list (list MinX MinY MinZ) (list MaxX MaxY MaxZ))
)