This paper proposes a new computer aided pattern design system(CAPDS)in which a uniformmathematical expression is used to construct different objects. In the geometric model, 3 B-splineis adopted as a line model. The ...This paper proposes a new computer aided pattern design system(CAPDS)in which a uniformmathematical expression is used to construct different objects. In the geometric model, 3 B-splineis adopted as a line model. The new system with uniform mathematical expression has the distin-guishing features: curve smoothness and fidelity, convenience to process graphic data in thedatabase and etc.. This paper presents the data structure, the program structure and also the implementation.展开更多
The concept of′Probe detector′is introduced in this paper with its application in geometricmodeling and graphics.In terms of the concept,the authors derive edge data from the CSG datarepresentation and establish a w...The concept of′Probe detector′is introduced in this paper with its application in geometricmodeling and graphics.In terms of the concept,the authors derive edge data from the CSG datarepresentation and establish a wireframe model.展开更多
Abstract For two rational quadratic B spline curves with same control vertexes, the cross ratio of four collinear points are represented: which are any one of the vertexes, and the two points that the ray initialing f...Abstract For two rational quadratic B spline curves with same control vertexes, the cross ratio of four collinear points are represented: which are any one of the vertexes, and the two points that the ray initialing from the vertex intersects with the corresponding segments of the two curves, and the point the ray intersecting with the connecting line between the two neighboring vertexes. Different from rational quadratic Bézier curves, the value is generally related with the location of the ray, and the necessary and sufficient condition of the ratio being independent of the ray's location is showed. Also another cross ratio of the following four collinear points are suggested, i.e. one vertex, the points that the ray from the initial vertex intersects respectively with the curve segment, the line connecting the segments end points, and the line connecting the two neighboring vertexes. This cross ratio is concerned only with the ray's location, but not with the weights of the curve. Furthermore, the cross ratio is projective invariant under the projective transformation between the two segments.展开更多
In the context of applying computer aided design tools to aircraft conceptualdesign, a sketch based approach is proposed to help designers turn their original concepts intocomplex numerical models that are usable for ...In the context of applying computer aided design tools to aircraft conceptualdesign, a sketch based approach is proposed to help designers turn their original concepts intocomplex numerical models that are usable for further analysis and optimization. This approachemphasizes the integration of general configuration and the layout of such components as engines,payloads, fuel tanks and landing gears, and the representation of a design scheme as uniform planesketches and three dimensional models. This paper presents the measures adopted to implement theapproach in a prototype system, including the object-oriented data structure, friendly graphicaluser interfaces and basic features of relevant modules. Several examples generated in the prototypeand applications of the results are finally outlined to illustrate the effectiveness of theapproach.展开更多
A Network Garment Style Design System (NGSDS) is proposed to enable the remote style structure drawing design of garment. After the development of the system structure based on network that consists of client end and ...A Network Garment Style Design System (NGSDS) is proposed to enable the remote style structure drawing design of garment. After the development of the system structure based on network that consists of client end and server end at two remote places, a multi-layer part database based on Oracle platform is presented to store information of different parts of garment style. With the acquirement of remote design data at server end using Http technology, the style design is ultimately implemented at the client end using Auto-connecting algorithms. One empirical example is given to show the implementation of the NGSDS.展开更多
文摘This paper proposes a new computer aided pattern design system(CAPDS)in which a uniformmathematical expression is used to construct different objects. In the geometric model, 3 B-splineis adopted as a line model. The new system with uniform mathematical expression has the distin-guishing features: curve smoothness and fidelity, convenience to process graphic data in thedatabase and etc.. This paper presents the data structure, the program structure and also the implementation.
文摘The concept of′Probe detector′is introduced in this paper with its application in geometricmodeling and graphics.In terms of the concept,the authors derive edge data from the CSG datarepresentation and establish a wireframe model.
文摘Abstract For two rational quadratic B spline curves with same control vertexes, the cross ratio of four collinear points are represented: which are any one of the vertexes, and the two points that the ray initialing from the vertex intersects with the corresponding segments of the two curves, and the point the ray intersecting with the connecting line between the two neighboring vertexes. Different from rational quadratic Bézier curves, the value is generally related with the location of the ray, and the necessary and sufficient condition of the ratio being independent of the ray's location is showed. Also another cross ratio of the following four collinear points are suggested, i.e. one vertex, the points that the ray from the initial vertex intersects respectively with the curve segment, the line connecting the segments end points, and the line connecting the two neighboring vertexes. This cross ratio is concerned only with the ray's location, but not with the weights of the curve. Furthermore, the cross ratio is projective invariant under the projective transformation between the two segments.
文摘In the context of applying computer aided design tools to aircraft conceptualdesign, a sketch based approach is proposed to help designers turn their original concepts intocomplex numerical models that are usable for further analysis and optimization. This approachemphasizes the integration of general configuration and the layout of such components as engines,payloads, fuel tanks and landing gears, and the representation of a design scheme as uniform planesketches and three dimensional models. This paper presents the measures adopted to implement theapproach in a prototype system, including the object-oriented data structure, friendly graphicaluser interfaces and basic features of relevant modules. Several examples generated in the prototypeand applications of the results are finally outlined to illustrate the effectiveness of theapproach.
文摘A Network Garment Style Design System (NGSDS) is proposed to enable the remote style structure drawing design of garment. After the development of the system structure based on network that consists of client end and server end at two remote places, a multi-layer part database based on Oracle platform is presented to store information of different parts of garment style. With the acquirement of remote design data at server end using Http technology, the style design is ultimately implemented at the client end using Auto-connecting algorithms. One empirical example is given to show the implementation of the NGSDS.
基金国家自然科学基金(the National Natural Science Foundation of Chinaunder Grant No.60672135)陕西省自然科学基金(the Natural Science Foundation of ShaanxiProvince of Chinaunder Grant No.07JK209)。
