Feature methodologies for heterogeneous object realization

Heterogeneous objects are objects composed of different constituent materials. In these objects, multiple desirable properties from different constituent materials can be synthesized into one part. Consequently, these objects can offer new material properties and multiple functionalities that cannot be obtained otherwise.; In order to obtain mass applications of such heterogeneous objects, efficient and effective design and fabrication methodologies for heterogeneous objects are crucial. Existing design and fabrication methodologies are highly sophisticated, but they are inefficient and even infeasible for handling heterogeneous objects. These methodologies are primarily developed for the production of homogeneous objects of which there is only one constituent material. The introduction of material variation throughout the objects adds a new dimension to the problem.; This dissertation presents feature based design and fabrication methodologies for heterogeneous object realization. We first examine the relationship between form features and material features in the heterogeneous objects. We then propose three types of synthesized material features in accordance with our examination of these features. Based on these proposed features, we develop a feature based design methodology for heterogeneous objects. Two enabling methods for this design methodology, combination of material features and material heterogeneity specification within each feature, are respectively researched and developed. A novel method, direct face neighborhood alteration, is developed to increase the efficiency of combination operations using heterogeneous material features. A physics (diffusion) based B-spline method is developed to efficiently specify material composition within each feature volume.; A feature based fabrication methodology is developed to facilitate the efficient manufacturing of these objects using layered manufacturing. This methodology introduces a new concept, feature interaction volume, which contributes to reducing the staircase effect inherent in layered manufacturing. Experimental results and quantitative analysis demonstrate significant build time can be saved using feature based fabrication methodology.