(defun 3dfaca (sss / p4_flag eps p1 p2 p3 p4)

	(setq eps 0.0001)
	(setq p1 (cdr (assoc 10 sss))
	      p2 (cdr (assoc 11 sss))
	      p3 (cdr (assoc 12 sss)))

	(if (< eps (distance (cdr (assoc 13 sss)) p3))
		 (progn
			(setq p4 (cdr (assoc 13 sss)))
	                (setq p4_flag 1)
		 )
	) 

	(if p4_flag (command "_3dpoly" p1 p2 p3 p4 "_c")
	            (command "_3dpoly" p1 p2 p3 "_c")
        ) 
)

;------------------------------------------------------------------------------
(defun C:3dfs2plin( / elementsatz i typ)
		
	(setq osmode_old (getvar "OSMODE"))
	(command "OSMODE" 0)

(alert "\n3D-FACEs zu 3DPoLYLINIEN
www.black-cad.de

wähle eine oder mehrere 3d-Fläche")	

	(setq elementsatz (ssget))

	(setq i -1)

(repeat (sslength elementsatz)
	(progn
		(setq i (+ 1 i))
		(setq typ (cdr (assoc 0 (entget (ssname elementsatz i)))))
		(if (= typ  "3DFACE")   (3dfaca(entget (ssname elementsatz i)))
					(princ "\nkeine 3d-Fläche")
		)
	(terpri)
	)
)

(command "OSMODE" osmode_old)
)