As a young kid I remember my dad in an AOL chat room chatting with Kai. We had KPT Bryce, Kai's Power Goo, etc. I loved those programs, but KPT Bryce is probably what I spent the most time with. I would just sit and stare at the antialiasing passes, making minor tweaks. As a kid it felt oddly intuitive in a way that I can't say I've experienced with most modern software. There was also a sense of discovery where you'd kind of dream about how the wireframes on the screen would be painted once you'd selected various textures and lighting effects to be applied.

One piece of software that most may not be familiar with which I see as very related to Kai's work is U&I software's MetaSynth. The UI feels similar to Kai's UIs, and it is unlike any other sound design tool I've ever used. I believe Eric Wenger of U&I is a MetaCreations fellow and also worked on KPT Bryce way back in the early days.