ISO/IEC 19775-1:2015，可扩展3D（X3D），定义了一个集成3D图形和多媒体的系统。从概念上讲，每个X3D文件都是一个基于3D时间的空间，其中包含可以通过各种机制动态修改的图形和听觉对象。ISO/IEC 19776的这一部分使用可扩展标记语言定义了X3D中抽象对象到特定X3D编码的映射。 每个XML编码的X3D文件: a.支持X3D抽象规范ISO/IEC 19775中定义的X3D文件的所有用途； b.以XML格式对X3D结构进行编码。 XML编码的X3D文件可以从使用其他X3D编码的文件中被引用，并且其本身可以引用使用其它X3D编码编码的其它X3D文件。这样的文件只能由符合所有使用的X3D编码的浏览器来处理。

ISO/IEC 19775-1:2015, Extensible 3D (X3D), defines a system that integrates 3D graphics and multimedia. Conceptually, each X3D file is a 3D time-based space that contains graphic and aural objects that can be dynamically modified through a variety of mechanisms. This part of ISO/IEC 19776 defines a mapping of the abstract objects in X3D to a specific X3D encoding using the Extensible Markup Language. Each XML-encoded X3D file: a. supports all of the purposes of X3D files defined in the X3D abstract specification ISO/IEC 19775; b. encodes X3D constructs in an XML format. An XML-encoded X3D file may be referenced from files using other X3D encodings and may itself reference other X3D files encoded using other X3D encodings. Such files can only be processed by browsers that conform to all of the utilized X3D encodings.