Well I don't think they were using any sort of sub-d primitives at that time, I guess those are all 'math' primitives that are resolution free, a bit like a Nurbs sphere, or other revolved geo ... maybe it was Nurbs ? I guess Groboto was also handling the rigging right ? It's a really strange tool, not sure I personally could use it for anything tho.

It does reminds me something like Organica from impulse in the late 90's ... the metaballs era ... decompose any shape like a collection of primitives, it's a really particular exercise !