The 3D rendering software behind films such as Toy Story, Monsters Inc and Harry Potter is to be given away free for non-commercial use.
RenderMan, which is developed by Pixar, has faced increased competition from rival animation rendering programmes such as VRay and Arnold.
Although Pixar, which is owned by Disney, produces its own films, it licenses RenderMan to rival studios.
The company has also cut the price of its software for commercial use.
In a statement, the firm said it would release a free version of RenderMan "without any functional limitations, watermarking, or time restrictions".
"Non-commercial RenderMan will be freely available for students, institutions, researchers, developers, and for personal use," it added.
Ian Dean, editor of computer graphics magazine 3D World, told the BBC the move "could be seen as a reaction to the rise of alternatives such as Arnold," but that Disney/Pixar are also looking to "build a community".
He added that RenderMan, which has been around for more than 25 years, was "very important at the higher end of the entertainment, animation and visual effects industries".