;; ! ****************************************************************************
;; ! GE_pist3d2d
;; ! ****************************************************************************
;; ! Function : Converts a 3D points list to 2D points list
;; ! Arguments:
;; !            'vlist'  - List of 3d points
;; !            'Mode'   - Can be eithe rof the strings
;; !                       "Zero"    - Sets all elevations to 0.0
;; !                       "Lowest"  - Sets the Z to the lowest value
;; !                       "Highest"  - Sets the Z to the highest value
;; !                       "First"   - Sets all elevations to first elevation
;; !                       "Average" - Averages all the elevations and sets
;; !                                   it to every point.
;; ! Action   : Returns the points list with the Z component reset to 0.0
;; ! Updated  : February 25, 1999
;; ! (C) 1999-2004, Four Dimension Technologies, Bangalore
;; ! e-mail   : rakesh.rao@4d-technologies.com
;; ! Web      : www.4d-technologies.com
;; ! ****************************************************************************

(defun GE_plist3d2d( vlist Mode / Z X )
(cond
	((= Mode "Zero")
		(setq Z 0.0)
	)
	((= Mode "Lowest")
		(setq Z (apply 'min (mapcar 'caddr vlist)))
	)
	((= Mode "Highest")
		(setq Z (apply 'max (mapcar 'caddr vlist)))
	)
	((= Mode "First")
		(setq Z (caddr (car vlist)))
	)
	((= Mode "Average")
		(setq Z (/ (apply '+ (mapcar 'caddr vlist)) (length vlist)))
	)
)
(mapcar '(lambda(x) (list (car x) (cadr x) Z)) vlist)
)