8 research outputs found

    3D CAD principles and applications

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    Patch Interpolation Using Edge-based Blending Function

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    By introducing the edge-based blending function derived from the surface-based one, we can capture the effects of the edges on the shape of the n-sided patch more directly. Because of the good natures of the edge-based blending function, the designers can manipulate it as well as the geometry of the boundary curves to design and modify the patch shape. In this paper, we have discussed the derivation of the edge-based blending function, its properties, especially the differences between ones for odd-sided and for even-sided patches, and easiness of designing it by the users. We have demonstrated its validty by showing several triangular, rectangular, and pentagonal patchs using the modifiable blending functions. 1. Introduction The need for the surface representation scheme to cover n-sided faces was pointed out during the first half of 1980's by several pioneers, for example, Gregory 3 , Sabin 6 , and Hosaka and Kimura 5 . Recent researches done by Loop and DeRose, Grim and Hug..

    XVL: A Compact And Qualified 3D Representation With Lattice Mesh and Surface for the Internet

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    Computer graphics systems and CAD/CAM systems are widely used and an abundance of 3D-Data in various fields exists. However, based on the VRML technique, it is difficult to send such 3D-Data through the Internet, because of the large data size. Transmission of practical and highly detailed 3D-Data through the Internet becomes a primary requirement. 1 Graduate School of Media and Governance, Keio University. 5322 Endo, Fujisawa, Kanagawa, 252-8520, Japan. {wakita, chiyo}@sfc.keio.ac.jp 2 {yajima, harada, toriya}@lattice.co.jp Therefore, a compact and qualified 3D-Data representation method is greatly required. This paper describes XVL (eXtended VRML with Lattice), a new framework for compact 3D-Data representation with high quality surface shape. By utilizing a freeform surface technique, qualified surfaces are transferred with a limited amount of data size and rendered. Free-form surfaces transferred by an efficient data structure are called lattice structure. This data structur..
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