1. A method for use in an object based imaging system wherein the shape and position of a plurality of objects in an image space are defined by respective sets of vectors and at least two of said objects may overlap one another, said method for determining whether pairs of said objects abut or overlap one another and comprising the acts of: generating a bit map of said image space from said respective sets of vectors, said bit map comprising a grid of pixels whose values are determined by the shape and location of said objects in said image space, each pixel of said bit map which corresponds to the location of more than one of said objects being assigned a value associated with only one of said objects whereby each pixel in said grid of pixels is assigned a single value; and determining which of said objects abut or overlap one another by examining said values of adjacent ones of said pixels.