Research in Solid Modeling: Boundary-to-CSG Conversion

实体建模研究：边界到CSG的转换

• 批准号: 9215463
• 负责人: Herbert Voelcker
• 金额: $ 26.99万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 1995-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9215463&HistoricalAwards=false
• 关键词: Research; Solid; Modeling; Boundary; CSG

The development of solid modeling as an industrially viable technology was paced by the development, in the 1970's, of theory and algorithms for boolean operations on solids, i.e. for converting constructive (CSG) representations into boundary representations (B-reps). Theory and algorithms for the inverse conversion, from boundary to CSG (called BCSG), were largely unknown prior to the work of Shapiro and Vossler in 1989-91. Their cell-based methods are mathematically sound and have been implemented experimentally, but several important practical issues remain open. This research addresses those issues through the following goals: (1) development of significantly better algorithms for cell-based BCSG conversion; (2) development of a publicly available implementation of BCSG, initially for a domain of natural quadric surfaces, that is usable with one or more open architecture (i.e. public) B-rep modeling systems; and (3) development of theory and techniques, using new algebraic-patch and constructive-shell representations, to enable BCSG conversion to accommodate freeform solids. This research will re-establish CSG as an industrially viable representation for solids, and will enable fully symmetric dual- representation modeling systems to be built which should be considerably more powerful than today's B-rep-only systems.

实体建模作为工业上可行的技术的发展是随着 1970 年代实体布尔运算理论和算法的发展而发展的，即将构造性 (CSG) 表示转换为边界表示 (B-reps)。 在 Shapiro 和 Vossler 于 1989-91 年开展工作之前，从边界到 CSG（称为 BCSG）的逆转换的理论和算法在很大程度上是未知的。 他们基于细胞的方法在数学上是合理的，并且已经通过实验实现，但几个重要的实际问题仍然悬而未决。 本研究通过以下目标解决这些问题：(1) 开发更好的基于细胞的 BCSG 转换算法； (2) 开发一种公开可用的 BCSG 实现，最初用于自然二次曲面域，可与一个或多个开放架构（即公共）B-rep 建模系统一起使用； (3) 发展理论和技术，使用新的代数补丁和构造壳表示，使 BCSG 转换能够适应自由形式的实体。 这项研究将重新建立 CSG 作为工业上可行的固体表示，并将能够构建完全对称的双表示建模系统，该系统应该比当今仅 B-rep 的系统强大得多。