Abstract: Most of the commercial CAD systems are fail to represent heterogeneous objects (HEO) since they are based on the premise that the objects under design are homogeneous in material composition, and the majority of existing approaches lack compatibility with traditional CAD software packages and rapid prototyping systems. An HEO modeling is approached, which employs tetrahedral solid cell and common stereo lithography data (STL) based on mapping relationship between HEO geometry and its materials. HEO is decomposed hierarchically as the sequence of solid, tetrahedral cells, STL facets and voxels. Each voxel of tetrahedral cell is defined by its space coordinate, facets vectors and material information. Furthermore, HEO exterior and interior geometry and material distributions are described. A systematic design and built process of HEO prototype is demonstrated as a case study. Results show that the proposed approach can facilitate the design of complex heterogeneous objects.

Key words: CAD model, Heterogeneous objects, Rapid prototyping