REPRESENTATION AND PROCESSING OF HETEROGENEOUS OBJECTS FOR RAPID PROTOTYPING

摘要

For fabricating heterogeneous objects by RP, a CAD model is required that contains both geometry and material information, but current solid modeling techniques can only represent the geometry information of objects. This paper presents an approach to represent and process heterogeneous objects by integrating material information along with geometry/topology information in the solid model. The standard exchange format, such as STEP, was adopted to exchange geometry information between the CAD system and heterogeneous solid modeling system. For material designing, reference entities were selected and material distribution information in terms of distance functions were specified together. The material information was incorporated with geometry/topology information by attaching distance functions to reference entities as their properties. The compositions at points inside a heterogeneous object can be evaluated by computing the distance from query points to the reference. In processing heterogeneous solid model, we discretized the continuous material distribution in a 2-D space rather than in a 3-D space. Furthermore, the slicing process goes along with the manufacturing process of heterogeneous objects concurrently. Therefore, much memory can be saved. Two examples are also described.