"Calibre script" implies batch mode (no GUI) but "click on the bump layer" says a layout viewer, at minimum. What tools do you want to use?
The Calibre DESIGNrev User's Manual (calbr_drv_user.pdf) has examples of adding layers, drawing polygons, and will tell you where on the viewer to look for your polygon's coordinates. The calbr_drv_ref.pdf manual has scripting examples. All this assumes, however, you are using the Calibre layout tools.