1. A method for interactively defining a virtual-world space based on real-world objects in a real-world space, comprising: (a) receiving an input identifying one or more reference points in the real-world space to define the virtual-world space; (b) receiving an input identifying one of the real-world objects to characterize into a virtual-world object, the real-world object being other than a user; (c) prompting, via an on-screen display, the user to select one or more object part locations on the real-world object, the object part locations being identified relative to an identifiable reference plane in the real-world space, the identifiable reference plane defined based on the reference points; (d) receiving an input identifying the object part locations selected by the user in response to said prompting; (e) extracting one or more parameters of the real-world object from the input identifying the object part locations; and (f) generating a virtual-world object in the virtual-world space using the extracted parameters of the real-world object.