[hatts]

Does someone have a link to an article -- or personal knowledge regarding -- the method zbrush uses to display a model? I vaguely remember hearing that it's some sort of pseudo-rendering.

Mostly curious how it's so fast and fluid.

[Polyxo]

Well things definitly get rendered but it's not the GPU doing this. Zbrush runs entirely on CPU which is quite extraordinary.
Also the way their 3 dimensional space is defined seems to be some sort of programmatically highly efficient extension of the 2.5D
workspace the software started with. Apart from that they are extremely effective in juggling resources. It's only the currently active
subtool which needs a lot of resources. That way one can display a hundred million polygons for as long as none of the subtools consumes
more than 4gb of memory.