as the tag for all red blocks using the information in the tag the camera 39 s visual sensing may be simulated for example if the camera is looking for blocks of a particular color it can request the identifier for all tags in the region corresponding to the camera 39 s viewing frustum where it is looking and find the intersecting tag that describes the desired color the same technique can be used to mark other relevant visual information with the value of its pattern without having to do real vision processing in simulation mode for example fig6 b shows another example of the graphical user interface 600 of the engineering tool where a dialog box enlarged in callout is used to supply the qr code for a tray running through the system in this case the string may provide the value that would normally be encoded in the arrangement of squares in the qr code it should be noted that the general principles discussed above may be extended to simulate the behavior of any physical sensor for example while fig6 a and 6b describe embodiments where the physical sensor may be a color checking component or a qr reader respectively the process of setting tag values and simulating behavior may be applied to any visually detectable or proximity based property of the components of the simulation environment moreover in some embodiments non visual properties of devices e g temperature pressure flow etc may be similarly simulated by the engineering tool using tags as discussed herein also in some embodiments external values such as coming from an external database or communication with an external processing unit may be simulated with tags and produced at runtime by generating tags dynamically fig7 illustrates an exemplary computing.