model or paper settings

I have a lisp that draw some things, after i select a point - like a reference point. If i select the point in model, those things will be drawn in model, and if i switch to paper, will be drawn in paper - like the point was selected in paper. I want to use my lisp both ways, if i work in model or in paper, but those things that should be made by lisp to be drawn always in model or paper - how to do it?

Use CTAB variable to check or set the current tab:

(getvar "CTAB")
(setvar "CTAB" "Model")

The LAYOUTLIST function will give you the list of layout tabs available in drawing.

(layoutlist)

(defun aspace nil
 (vlax-get
   (setq *acdoc*
     (cond
       ( *acdoc* )
       ( (vla-get-activedocument
           (vlax-get-acad-object)
         )
       )
     )
   )
   (cond
     ( (eq AcModelSpace (vlax-get *acdoc* 'ActiveSpace))
       'ModelSpace
     )
     ( 'PaperSpace )
   )
 )
)

Example:

(vlax-invoke (aspace) 'addline '(0. 0. 0.) '(1. 1. 0.))

Taking into consideration the extra information received through PM, my answer is yes, it is possible to take a point on a tab, then switch to other one and use that point as reference for a draw operation. Please see example below:

(setvar "CTAB" "Model")
(setq point1st (getpoint "\nIndicate insertion point: "))
(setvar "CTAB" (car (layoutlist)))
(command "_CIRCLE" "_non" point1st 5.0)

But, I'm not sure how to pause the routine evaluation to allow user to indicate the new tab. You may do that by a dialog or by a prompter (GETSTRING with INITGET), although this may not be reliable for a long list of layouts, long and/or based on a patter names for layout or even usage of space(s) on layout names.

I hope someone else can suggest you a better solution.