; Set Plot Transparency ON/off (CAD Studio, 2017 - www.cadstudio.cz  www.cadforum.cz)

(vl-load-com)

(defun c:AllLOT (/ aDoc Layouts itm)

(defun LayoutTransparency (layout OnOff / xType xData)
  (setq xData (vlax-make-safearray vlax-vbVariant '(0 . 1)))
  (setq xType (vlax-make-safearray vlax-vbInteger '(0 . 1)))
  (vlax-safearray-fill xData (list (vlax-make-variant "PLOTTRANSPARENCY")(vlax-make-variant OnOff)))
  (vlax-safearray-fill xType (list 1001 1071))
  (vla-setXdata layout xType xData)
  (entmod (entget (vlax-vla-object->ename layout) '("*")))
)

  (setq	aDoc (vla-get-activedocument (vlax-get-acad-object))
		Layouts (vla-get-layouts aDoc)
  )
  (foreach
	   itm
		  (layoutlist) ; just layouts, no Model...
; or:
;		  (append '("Model") (layoutlist)) ; incl. Model tab
    (LayoutTransparency (vla-item Layouts itm) 1) ;       1=ON 0=off
  )
 (princ)
)