A real-time computer-based viewing system comprising a database of software objects, wherein at least one of said software objects corresponds to a physical structure which is to be viewed by said system; a sensor for acquiring real-time data about said physical structure when said physical structure is located within that sensor's data acquisition field, wherein said sensor is capable of being moved about relative to said physical structure; an additional software object incorporating real-time data acquired by said sensor; registration means for positioning said additional software object in registration with said software objects stored in said database, the registration being a function of the position of the sensor vis-a-vis the physical structure; and processing means for generating an image from said software objects contained in said database, based upon a specified point of view.