Well Maya (a rather expensive 3D designa and animation program) is the primary user of Renderman, at least that is what Pixar Studio's rely. It is my understanding that most 3D applications that have animation features built in will work with Renderman. I downloaded it not for the purposes of animation, rather, I generally only create 3D stills, and usually top down only for use in my map designs. I'm planning to create detailed map objects in Nendo exported to .3DS format, imported to Renderman and run as a single frame rendering. I'm pretty sure Renderman also works by command-line, instead of being command line only.