The Clockworks is an object-oriented computer animation system developed at RPI's Center for Interactive Computer Graphics. The Clockworks has the ability to model and graphically simulate complex 3-D engineering processes. Its interactive capabilities also allow it to be used as a design tool. Object-oriented concepts have been utilized in developing its high-level architecture and its low-level implementation. The Clockworks is defined as a collection of objects which communicate with the user and each other via messages. The actual implementation involved the creation of an object-oriented programming methodology in C and Unix. The complete system provides a rich research environment for exploring modeling, scripting and rendering. It also provides an interactive environment for visual analysis of complex interacting structures.