ISO/IEC 19775-1:2004 defines the architecture and base components of X3D. ISO/IEC 19775, X3D, defines a software system that integrates network-enabled 3D graphics and multimedia. Conceptually, each X3D application is a 3D time-based space that contains graphic and aural objects that can be dynamically modified through a variety of mechanisms.

The semantics of X3D describe an abstract functional behaviour of time-based, interactive 3D, multimedia information. ISO/IEC 19775-1:2004 does not define physical devices or any other implementation-dependent concepts (e.g. screen resolution and input devices). ISO/IEC 19775-1:2004 is intended for a wide variety of devices and applications, and provides wide latitude in interpretation and implementation of the functionality. For example, ISO/IEC 19775-1:2004 does not assume the existence of a mouse or 2D display device.

Each X3D application:
implicitly establishes a world coordinate space for all objects defined, as well as all objects included by the application;
explicitly defines and composes a set of 3D and multimedia objects;
can specify hyperlinks to other files and applications;
can define programmatic or data-driven object behaviours;
can connect to external modules or applications via programming and scripting languages;
explicitly declares its functional requirements by specifying a profile;
can declare additional functional requirements by specifying components.