Shape modeling is fundamental to the analysis of dynamic environment and motion around asteroid. Chang＇E- 2 successfully made a flyby of Asteroid 4179 Toutatis and obtained plenty of high-resolution images during the...Shape modeling is fundamental to the analysis of dynamic environment and motion around asteroid. Chang＇E- 2 successfully made a flyby of Asteroid 4179 Toutatis and obtained plenty of high-resolution images during the mis- sion. In this paper, the modeling method and preliminary model of Asteroid Toutatis are discussed. First, the optical images obtained by Chang＇E-2 are analyzed. Terrain and silhouette features in images are described. Then, the modeling method based on previous radar model and preliminary information from optical images is proposed. A preliminary polyhedron model of Asteroid Toutatis is established. Finally, the spherical harmonic coefficients of Asteroid Toutatis based on the polyhedron model are obtained. Some parameters of model are analyzed and compared. Although the model proposed in this paper is only a preliminary model, this work offers a valuable reference for future high-resolution models.展开更多
After undergoing wireframe modeling, surface modeling and solid modeling, a unified product model, which holds a variety of constraints in engineering, supports design process, and unifies the wire frame, surface mode...After undergoing wireframe modeling, surface modeling and solid modeling, a unified product model, which holds a variety of constraints in engineering, supports design process, and unifies the wire frame, surface modeling, and solid modeling,is a general tendency of modeling technology. A discussion is presented here on how tobuild a unified product model by using the complex method. The concept of complex inalgebraic topology is introduced into the model and a new B-REP representation of thenon-manifold model is given --Identification Edge Structure. Based on it, some basicoperators and high-level operators are built. The model has a rigorous mathematicalbasis, and is flexible and easy to extend, and holds the lamina face, lamina edge andlamina vertex. As a result, the variety of constraints in engineering, such as parametricconstraints, optimization methods, fuzzy constraints, artificial intelligent, etc., can beadded to the system. The model may form the kernel for the implementation of the nextgeneration CAD system --intelligent CAD system.展开更多
基金supported by the National Basic Research Program of China("973" Program)(2012CB720000)the National Natural Science Foundation of China(11102020)the Program for New Century Excellent Talents in University and Beijing Higher Education Young Elite Teacher Project
文摘Shape modeling is fundamental to the analysis of dynamic environment and motion around asteroid. Chang＇E- 2 successfully made a flyby of Asteroid 4179 Toutatis and obtained plenty of high-resolution images during the mis- sion. In this paper, the modeling method and preliminary model of Asteroid Toutatis are discussed. First, the optical images obtained by Chang＇E-2 are analyzed. Terrain and silhouette features in images are described. Then, the modeling method based on previous radar model and preliminary information from optical images is proposed. A preliminary polyhedron model of Asteroid Toutatis is established. Finally, the spherical harmonic coefficients of Asteroid Toutatis based on the polyhedron model are obtained. Some parameters of model are analyzed and compared. Although the model proposed in this paper is only a preliminary model, this work offers a valuable reference for future high-resolution models.
文摘After undergoing wireframe modeling, surface modeling and solid modeling, a unified product model, which holds a variety of constraints in engineering, supports design process, and unifies the wire frame, surface modeling, and solid modeling,is a general tendency of modeling technology. A discussion is presented here on how tobuild a unified product model by using the complex method. The concept of complex inalgebraic topology is introduced into the model and a new B-REP representation of thenon-manifold model is given --Identification Edge Structure. Based on it, some basicoperators and high-level operators are built. The model has a rigorous mathematicalbasis, and is flexible and easy to extend, and holds the lamina face, lamina edge andlamina vertex. As a result, the variety of constraints in engineering, such as parametricconstraints, optimization methods, fuzzy constraints, artificial intelligent, etc., can beadded to the system. The model may form the kernel for the implementation of the nextgeneration CAD system --intelligent CAD system.
