Vrui is both a collection of software and a community of XR developers and scientific investigators and educators who use XR for research and teaching.
The Vrui Toolkit is a comprehensive development framework designed to facilitate the creation of immersive virtual reality applications. It provides a suite of tools and libraries that enable developers to build VR software with advanced 3D user interfaces, supporting a wide range of input devices and display systems. Vrui emphasizes flexibility and scalability, making it suitable for applications in scientific visualization, data exploration, and other fields requiring interactive 3D environments.
Applications are developed using the Developer Toolkit and deployed as part of Vrui installation to provide specific XR experiences. For example, the LiDAR Viewer is an interactive application for processing, visualizing, and analyzing large 3D point cloud data produced by terrestrial or airborne LiDAR scanning. Links to the repositories of Vrui applications that are released as Open Source Software (OSS) and whose developer(s) commit to upholding our Code of Conduct appear in Vrui Organizations list of repositories on this page.
Our community consists of Vrui users and developers. As of March, 2025, we are aware of approximately 2,000 Vrui users! Please see our Code of Conduct for detailed information about Vrui values and standards.
As noted above, Vrui software elements fall into one of two classes:
- The Vrui Developers Toolkit (the Vrui Core)
- Vrui applications
The Vrui Developer Toolkit provides a base level of computational elements that provide abstracted access to specific computational, display, and input/output hardware devices.
Vrui applications provide specific XR user experiences such as immersive 3D video experiences, the ability to inhabit a scene created from LiDAR data, or a virtual meeting room. User experiences are managed and delivered via Vrui applications, which pass information between the Vrui Developer Toolkit and XR devices.
Vrui supports the development of correct, portable, and usable applications across various environments, from desktop systems to CAVEs or head-mounted displays, and Augmented Reality systems.
The primary task of a virtual reality (VR) development toolkit is to shield an application developer from the particular configuration of a VR environment such that applications can be developed quickly and in a portable and scalable fashion across multiple XR environments. Three important parts of this overarching goal are encapsulation of the display environment, of the distribution environment, and of the input device environment.
A toolkit should provide OpenGL rendering contexts that are set up in such a fashion that rendering a model in user-specific coordinates will display that model on all rendering surfaces (monitors, screens, head-mounted displays) in correct head-tracked stereographic mode.
As larger VR environments require more than one computer to operate, the detail aspects of distribution (number of computers, connection topology, etc.) should be hidden by the toolkit. In principle, there are at least three ways to distribute a rendering environment:
- Split first: An application is replicated on all computers and synchronized by distributing input device and ancillary data.
- Split middle: A shared data structure, e.g., a scene graph, is used to transmit data from one application computer to all rendering computers.
- Split last: The OpenGL API call stream is broadcast from one application computer to all rendering computers, e.g., using Chromium.
A toolkit should also hide the difference between a distributed rendering environment running on a cluster of individual computers and one running on a shared-memory multi-CPU computer with several independent graphics pipes.
There are a wide variety of different vendors, models, and protocols to connect VR input devices such as space balls, space mice, 6-DOF trackers, wands, data gloves, etc., to the computers comprising a VR environment. A toolkit must hide these differences in hardware and provide a uniform view of the set of connected input devices. Furthermore, a toolkit should provide mechanisms not only to hide the hardware details of the input device environment but also the number and configuration of input devices.
An application should be written without aiming for a particular input environment (such as "CAVE wand and head tracker" or "stylus, two pinch gloves, and head tracker"). Instead, the toolkit should provide a layer that allows an application to specify its input requirements at a higher level and allows a user to map input devices to these requirements.
For example, an application might offer a tool to grab an application-specific object and move it, and the user might ask the Vrui toolkit, at run-time, to bind that tool to, for example, the trigger button on the right-hand VR controller.
Most existing VR toolkits cover the first aspect well; some VR toolkits cover the second aspect by using any one of the listed distribution schemes, but no toolkit we found covers the third aspect.
Vrui applications interact with the Vrui Developer Toolkit to provide fully scalable and portable software. These applications run across a wide range of VR environments, from a laptop with a touchpad to desktop environments with special input devices such as space balls. They also support fully immersive VR environments, including a single-screen workbench to a multi-screen tiled display wall, CAVEs, and modern commodity head-mounted displays such as the HTC Vive or Valve Index.
Applications using the Vrui VR toolkit are written without a particular input environment in mind. Vrui-enabled VR environments are configured to map the available input devices to application functions such that the application appears to be written natively for the environment it runs on.
The Vrui Developer Toolkit and Vrui applications can be found on GitHub. Independent user and contributor documentation, support files, issues, and discussion boards are associated directly with each Vrui Organization repository. Please refer to the Contributing Guide for details on how to ask questions, report bugs, suggest enhancements, and more. In addition, please refer to the Documentation Website for more detailed documentation instructions.