How to create shielded path?

Hi,

 I have written the following code for creating a shielded path. The below mentioned code is having a fix set of coordinates: i.e.  "pts". How to add the functionality that a user can draw shield where ever he feels like:

;; Create a shielded path
procedure( shield()
errset(
(let (cv layer purpose list_draw_layer tech width1 tfId)
cv= geGetEditCellView()
layer = car(leGetEntryLayer()) ;displays layer on LSW is taken
purpose = cadr(leGetEntryLayer()); displays drawing or pin on the selected lsw
list_draw_layer =list(layer purpose)
tech = techGetTechFile(geGetWindowCellView()); rule deck file id is stored in tech
width1 = techGetSpacingRule(tech "minWidth" layer) ; the minimum width is stored in width1
rodCreatePath(
?name "shield"
?layer list( layer purpose )
?pts list(2:-15 2:-5 15:-5 15:-15)   If this is not fixed, the user can draw shield anywhere. What changes are needed?
?width .8
?justification "center"
?cvId cv
?offsetSubPath
list(
list(
?layer list( layer purpose )
?justification "left"
?sep 1
?width .4
) ;end of offset sublist1
list(
?layer list( layer purpose )
?justification "right"
?sep 1
?width .4
) ;end of offset sublist2
) ;end of offset list of lists
) ;end of rodCreatePath
) ; end of let
t
) ; end of errset
) ; end of procedure