(defun c:cv ( / height vertex pt lst)
; (command "layer" "make" "ceiling" "thaw" "ceiling" "set" "ceiling" "")
(setq height (getreal "enter height: "))
(setq vertex (getpoint "pick a vertex: "))
(setq pt (getpoint "pick point: "))
(while (not (eq pt nil))
(setq lst (cons pt lst))
(setq pt (getpoint "pick point: ")))
(setq lst (reverse lst))
(while (not (eq (second lst) nil))
(command "3dface" (ceiling_pt (first lst) height) (ceiling_pt (second lst) height) (ceiling_pt vertex height) "" "" "")
(setq lst (cdr lst))))