X3D (Extensible 3D Graphics) is an open, royalty-free ISO standard for defining 3D computer graphics. It is the successor to VRML (Virtual Reality Modeling Language) and offers a more modern and flexible architecture. X3D files describe 3D scenes and objects using a scene graph structure. This scene graph contains nodes that represent geometric shapes, appearances (materials, textures), transformations, animations, and interactions. X3D supports a wide range of 3D graphics features, including polygonal geometry, NURBS surfaces, animation, lighting, texturing, audio, video, and user interaction. It is designed to be platform-independent and can be used for various applications, such as CAD, medical visualization, scientific visualization, architectural walkthroughs, and interactive 3D games. X3D files are typically encoded in XML, but other encodings like binary and compressed binary are also supported. The standard defines several profiles, which are subsets of the full X3D functionality, to cater to different application requirements and hardware capabilities. These profiles ensure interoperability between different X3D implementations.