AbstractIn contrast to traditional rapid prototyping of homogeneous objects, fabrication of heterogeneous objects (using layered manufacturing technologies) requires additional material information to be incorporated along with the object’s geometries. The paper presents relevant data structures and algorithms for virtual prototyping of heterogeneous objects. Heterogeneous CAD models, which represent the ideal digital heterogeneous objects, are first described. Interrogation of the material compositions from the CAD models is then carried out at runtime. Voxels (with location-specific material properties) are subsequently created and maintained in a dynamic scan-line structure, layered-section structure and the virtual-object structure. The proposed data structures and the associate algorithms have been successfully applied in virtually prototyping of heterogeneous objects. Virtually fabricated heterogeneous object examples are provided.