The problem in which the 3D motion of an object corresponding to a known polyhedral model is to be computed using only the motion of edge features in a continuous stream of 2D images is considered. Advantage is taken of the spatiotemporal density of the input signal and the limitations of long-range trajectory-prediction methods are avoided. Two parallel algorithms which use feature-based, short-range (spatiotemporally local) motion processes to achieve real-time tracking of modeled objects are presented. Both algorithms have been implemented and tested on a tightly coupled multiprocessor system consisting of an Aspex Pipe for low-level image-feature computations and a Sequent Symmetry for high-level model-based computations. An analysis is given of the actual performance limits of each method using the current hardware configuration.>