An open FBD system for generalized orthohedral components

This book proposes a feature-based design approach for three dimensional block structured components with generalized orthohedral geometry. The component is viewed as a collection of blocks connected by topological links. The geometry and topology are explicitly de¿ned. The geometry of the feature consists of an external shape and an internal shape, while the topology is modeled using a graph. The basic external shape of each block in a component is a rectangular parallelopiped which ¿xes overall size and location of the block. Using the idea of encapsulation, families of blocks with di¿erent internal shapes can be developed; all these internal shapes are assumed to be encapsulated in a block with rectangular external shape. The simple nature of the external shapes makes it easier to de¿ne operations like create, addition/deletion of blocks, topological connectivity speci¿cations, etc. The internal shape provides the necessary information for geometry speci¿c operations such as display, volume computation, etc. Dimensioning and tolerancing support is provided using a graph representation.