visitOSPRay is a VisIt plugin which creates a custom view using vtkOSPRay for rendering. The code for VisIt, the plugin, and the base VTK code are all contained in the visitOSPRay code tree.
VisItOSPRay is currently pre-alpha and no master branch version has been released. Intrepid souls who are tolerant to early-release code may clone the current development version from the dev branch.
The base VTK code without ParaView is contained in the VTK directory and makes up vtkOSPRay. vtkOSPRay is a VTK module which utilizes Intel's OSPRay ray tracing framework (http://ospray.github.io) for rendering.
vtkOSPRay is bundled with visitOSPRay. VTK support is built as part of the visitOSPRay build process.