This research will develop representations and algorithms for generating assembly sequences of products. The problem is theoretically of combinatorial complexity. A method has been developed to describe axially symmatic developed to describe assemblies based upon high-level engineering features and mating conditions. A rule-based algorithm derives a graph-structure corresponding to an exploded-view of the assembly. Interpreting this information as precedences among components, another program generates selected assembly sequences. This research will extend the methodology to general, three- dimensional cases. The importance of this research is twofold; automatically providing the designer with information regarding the assembly process can significantly enhance the simultaneous engineering process; and by showing that computerized spatial reasoning is possible with high-level input descriptions, powerful design assistants can be developed for computer aided design systems.