Blue Moon Rendering Tools, or BMRT, was one of the most famous RenderMan-compliant photorealistic rendering systems and was a precursor to NVIDIA's Gelato renderer. It was distributed as freeware. BMRT was a popular renderer with students and other people who were trying to learn the RenderMan interface. It also had some features PhotoRealistic RenderMan did not have at time, for example, ray tracing. Even Pixar used BMRT for ray tracing before PRMan had such features. According to Exluna, it was used for 3D rendering in movies such as A Bug's Life, Stuart Little, The Cell, Hollow Man, and Woman on Top.