Creature House's "Expression". It was a natural-media vector art program, with amazingly snappy performance on early-2000 era machines. They got eaten by Micros

Creature House's "Expression". It was a natural-media vector art program, with amazingly snappy performance on early-2000 era machines. They got eaten by Microsoft right around the time I stopped being a broke college student and could actually buy a copy, so I ended up learning Illustrator inside out instead. I still miss its "freeze layer" feature. Got a complex vector layer? Freeze it: the program would cache a bitmap copy of the whole layer with whatever complex transparency you had, lock the layer for editing, and use that cached image for the preview render as you worked.