This paper presents a visual servoing system which incorporates a novel three-dimensional model-based tracking system. This tracking system extends constrained active contour tracking techniques into three dimensions, placing them within a Lie algebraic framework. This is combined with modern graphical rendering technology to create a system which can track complex three dimensional structures in real time at video frame rate (25 Hz) on a standard workstation without special hardware. The system is based on an internal CAD model of the object to be tracked which is rendered using binary space partition trees to perform hidden line removal. The visible features are identified on-line at each frame and are tracked in the video feed. Analytical and statistical edge saliency are then used as a means of increasing the robustness of the tracking system.