工业自动化系统与集成 用于三维可视化的JT文件格式规范 第3部分：版本2

[中文适用范围]： 本文件定义了用于3D可视化和轻量级几何及产品制造信息（源自CAD系统）查询的文件格式的语法和语义，使用不需要CAD系统全部功能的可视化软件工具。 本文件已被采纳为ISO 10303系列中的3D可视化能力补充。 ISO 10303系列是用于工程数据交换、共享和产品定义信息在产品生命周期内长期存档的ISO标准。 在本文件中，3D可视化被定义为在屏幕或其他媒体上对表示对象、信息或计算过程结果的数据集进行图形和文本3维表示的可视化呈现，以便人类通过观察可视化数据做出决策。 文件格式支持以下信息： — 面信息（三角形），使用几何压缩技术存储； — 视觉属性，如灯光、纹理和材料； — 产品制造信息，如尺寸、公差和其他属性； — 边界表示（b-rep）实体模型形状表示； — 配置表示； — 交付方法，如内容的异步流传输。 本文件未指定文件格式查看或处理的运行时架构的实现或定义。 [外文原描述]： This document defines the syntax and semantics of a file format for the 3D visualization and interrogation of lightweight geometry and product manufacturing information derived from CAD systems, using visualization software tools that do not need the full capability of a CAD system. This document has been adopted as a 3D visualization capability in addition to the ISO 10303 series. The ISO 10303 series are the ISO standards adopted for the engineering data exchange, sharing and long-term archiving of product definition information throughout the product lifecycle. In this document 3D visualization is defined as the visual presentation on a screen or another media of graphical and textual 3 dimensional representations of a set of data representing an object, information or results of a computational process in order to enable decision process by a human looking at the data visualized in a medium. The file format supports the following information: — facet information (triangles), stored with geometry compression techniques; — visual attributes such as lights, textures and materials; — product manufacturing information, such as dimensions, tolerances and other attributes; — boundary representation (b-rep) solid model shape representations. Several alternatives are available, including a representation based on the geometry standard defined in ISO 10303; — configuration representations; — delivery methods such as asynchronous streaming of content. The document does not specify the implementation of, or definition of a run-time architecture for viewing or processing of the file format.