Odd, even if the app worked and was free the wish was for an osnap added to AutoCAD. Doesn't sound like a wish granted to me.
For now here's a couple macros you can add for osnaps:
Snap, MidObject
Code:
^P_non (or midobj (load "midobj.lsp")(princ))(midobj)
Snap, Fraction Between 2 Points
Code:
(setvar "USERR1" (getreal "Fraction of the distance between pick points: "));\'cal plt(cur,cur,getvar(USERR1));
Snap, Centroid
Code:
^P(or C:pc1 (load "pc1.lsp"))(pc1)
Snap, Centroid which is probably what you're looking for requires "pc1.lsp".
Code:
;Center of closed polygon
;^P(or C:pc1 (load "pc1.lsp"))(pc1)
; (load "pc1.lsp")(pc1)
(defun pc1 ( / acdoc acspc acsel reg pt) (vl-load-com) ;; pc.lsp by Lee Mac modified for transparent osnap.
(setq acdoc (vla-get-ActiveDocument (vlax-get-acad-object))
acspc (vlax-get-property acdoc (if (= 1 (getvar 'CVPORT)) 'Paperspace 'Modelspace))
)
; (if (ssget "+.:E:S")
(if (ssget "+.:E:S" '((0 . "LWPOLYLINE") (-4 . "&=") (70 . 1)))
(progn
(vlax-for obj (setq acsel (vla-get-ActiveSelectionSet acdoc))
(setq pt(trans (vlax-get (setq reg (car (vlax-invoke acspc 'addregion (list obj)))) 'Centroid) 1 0))
(vla-delete reg)
)
(vla-delete acsel)
)
)
pt
)