The goal of the "OpenRT Real Time Ray Tracing Project" was to develop ray tracing to the point where it offers an alternative to the current rasterization based approach for interactive 3D graphics. Therefore the project consisted of several parts: a highly optimized ray tracing core, the OpenRT-API, which is similar to OpenGL

OpenGL

OpenGL is a standard specification defining a cross-language, cross-platform API for writing applications that produce 2D and 3D computer graphics. The interface consists of over 250 different function calls which can be used to draw complex three-dimensional scenes from simple primitives. OpenGL...

, and many applications ranging from dynamically animated massive models and global illumination, via high quality prototype visualization to computer games.

OpenRT was not Open Source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

; it was intended to be an open API similar to OpenGL

OpenGL

OpenGL is a standard specification defining a cross-language, cross-platform API for writing applications that produce 2D and 3D computer graphics. The interface consists of over 250 different function calls which can be used to draw complex three-dimensional scenes from simple primitives. OpenGL...

.