I saw that in other scripts that this kind of dotted frame is created.
May I know how to create these?
Start by creating a Sketch Object, then right click and Send to Rhino.
In Rhino, you can draw a new curve, in your case a rectangle. Back in GH, righ click the Sketch Object again and this time Load from Rhino. Selct the rectangle in the Rhino viewport.
Finally in GH you can choose color and line style.