Complex components are often decomposed into smaller elements in order to simplify the overall manufacturing processes. Inspired by this observation the aim of the research reported here is to automatically sub-divided models to generate sets of interlocking components that can be easily manufactured, and assembled, to form the desired shape. Central to the algorithm is a novel feature recognition technique that both identifies and separates protrusions bounded by complex surface geometries. The method adopted for partitioning an object also generates complimentary male/female (i.e. matching protrusion/depression) assembly features at the interface between components. In contrast to previous academic work, that has described algorithms for the sub-division of mould cavities, this paper describes a method for separating protrusions from the complex surfaces frequently found on components manufactured by, say, casting. The objective is to enable production of large complex components on rapid prototyping machines whose build volume is less than the size of the desired component. A novel heuristic, that uses edge curvature continuity to direct the search, guides the construction of protrusion boundaries. The resulting subdivision is represented as a cellular model that can be decomposed into separated manifold solids. After describing the algorithm and presenting some examples of its application the paper ends by discussing the approaches limitations.