Z is new a set of tools for simultaneous modeling in Houdini and ZBrush.
An example of modeling in both programs at the same time:
Basically, the toolkit allows to focus on modeling in both apps, so you don’t need to click a lot in order to import or export. It also lets you quickly import existing geometry from ZBrush with “Z Import” tool.
What is more, there is a tool “ZRemesher” for quick automatic retopology allowing users to do retopology automatically without unnecessary actions.
You can learn more here.