General

Extensible 3D (X3D) is a software standard for defining interactive web- and broadcast-based 3D content integrated with multimedia. X3D is intended for use on a variety of hardware devices and in a broad range of application areas such as engineering and scientific visualization, multimedia presentations, entertainment and educational titles, web pages, and shared virtual worlds. X3D is also intended to be a universal interchange format for integrated 3D graphics and multimedia. X3D is the successor to the Virtual Reality Modeling Language (VRML), the original ISO standard for web-based 3D graphics (ISO/IEC 14772). X3D improves upon VRML with new features, advanced application programmer interfaces, additional data encoding formats, stricter conformance, and a componentized architecture that allows for a modular approach to supporting the standard.

This section provides a background to the design objectives behind the development of X3D, an overview of the features of X3D and a description of the X3D specification process.

Design objectives

X3D has been developed to meet a specific set of market and technical requirements. To meet these requirements, X3D has adopted the following design objectives:

• Separate the runtime architecture from the data encoding
• Support a variety of encoding formats, including the Extensible Markup Language (XML)
• Add new graphical, behavioral and interactive objects
• Provide alternative application programmer interfaces (APIs) into the 3D scene
• Define subsets of the specification ("Profiles") that meet different market needs
• Allow for the specification to be implemented at varying levels of service
• Eliminate, where possible, unspecified or underspecified behaviors

X3D features

X3D has a rich set of features to support applications such as engineering and scientific visualization, multimedia presentations, entertainment and educational titles, web pages, and shared virtual worlds. The X3D feature set includes:

• 3D graphics - Polygonal geometry, parametric geometry, hierarchical transformations, lighting, materials and multi-pass/multi-stage texture mapping
• 2D graphics - Text, 2D vector and planar shapes displayed within the 3D transformation hierarchy
• Animation - Timers and interpolators to drive continuous animations; humanoid animation and morphing
• Spatialized audio and video - Audiovisual sources mapped onto geometry in the scene
• User interaction - Mouse-based picking and dragging; keyboard input
• Navigation - Cameras; user movement within the 3D scene; collision, proximity and visibility detection
• User-defined objects - Ability to extend built-in browser functionality by creating user-defined data types
• Scripting - Ability to dynamically change the scene via programming and scripting languages
• Networking - Ability to compose a single X3D scene out of assets located on a network; hyperlinking of objects to other scenes or assets located on the World Wide Web
• Physical simulation - Humanoid animation; geospatial datasets; integration with Distributed Interactive Simulation (DIS) protocols
• Geospatial positioning - Ability to accurately position X3D scene objects geospatially.
• CAD geometry – ability to represent CAD models mapped from CAD systems.
• Layering – Ability to organize X3D scenes into rendering groups so that objects in each layer can overlay objects in underlying layers.
• Support for programmable shaders – Ability to replace the X3D lighting model with custom shader programs.
• Particle systems – Ability to generate systems of particles that can represent fire, smoke, and other such effects.

For a complete list of X3D features, consult the component descriptions in clauses 7 through 40 of this part of ISO/IEC 19775.