If I recall they were marketed as “screamers” for Lightwave3D distributed rendering. The main customers seemed to be the 90s TV visual effects houses (Babylon 5 etc).
I ran a Softimage house in the mid-to-late 90s and we had SGI Indigo workstations and a Dec Alpha mental ray render farm of about 30 machines or so. There were certain renders, scenes, particularly anything with ray marching or volumetric light, where we couldn't have the SGIs participate in the render because their contributions were slightly different and resulted in a distinct checkerboard look.
I loved Softimage — sad when the big 3D apps all consolidated and we lost the competitive development of Wavefront / Softimage / Alias. I’ve been getting into Houdini this year — the app is still going strong, and actually affordable (vs back then when these apps, let alone the machine, cost as much as a car).
We had a seat of Prisms, the pre-Houdini offering from SideFX, purchased solely for one job. I found it inscrutable and the documentation was… well… it seemed as though the writer(s) just gave up even trying to explain anything.
