1. A method for configuring a failsafe monitoring device that failsafely monitors the operation of an automated machine or installation that defines a hazardous area, the failsafe monitoring device comprising at least one image recording unit adapted to generate a three-dimensional image of a spatial area that includes the hazardous area and an evaluation unit connected to said image recording unit for monitoring in real-time the spatial area and failsafely interrupting or altering the operation of said automated machine or installation in response to the detection of a predefined event, the method comprising the steps of: connecting a non-failsafe programmable computer having a display device to said monitoring device and using said computer to configure a safety zone outside the hazardous area and within said spatial area, wherein said configure step further comprises the steps of: recording a true three-dimensional image of the spatial area by means of the at least one image recording unit and displaying a representation of said true three-dimensional image on the display device, defining a virtual boundary between the safety zone and the hazardous area by generating at least one variable geometry element with a selected dimensional configuration and position within said spatial area, with the at least one variable geometry element being superimposed in the selected position onto the displayed representation, generating a data record representing the selected dimensional configuration and position of the at least one variable geometry element in the spatial area, and transferring said data record to said evaluation unit of said failsafe monitoring device; wherein the evaluation unit thereafter checks the plausibility of said data record, and further wherein said failsafe monitoring device thereafter monitors the spatial area to detect when an object breaches the virtual boundary between the safety zone and the hazardous area defined by the at least one variable geometry element, said breach comprising said predefined event.