[julienmarie]

Quantrix Modeler is a successor of Improv. I personally love it, but pricing is quite steep.

[spitfire]

Quantrix modeler is actually the successor to Quantrix for nextstep. Quantrix was a contemporary of Improv. Not sure I remember which came first. But Quantrix was the better of the two.

I'm collecting a pile of "good ideas"... Someday I'll do something with it.