Z is a set of tools for simultaneous modeling in Houdini and ZBrush.
Import and export of the geometry occurs automatically when you switch between ZBrush and Houdini windows.
You don't need to worry about the files in which the geometry is stored.
An example of modeling in both programs at same time:
1. Create a model in Houdini.
2. Now when you need to use ZBrush modeling tools activate tool "Z Export". As a result, ZBrush will start (if it is not running) and the geometry will be immediately ready for modeling.
3. Next, when you have finished working in ZBrush, simply activate the Houdini window, for example, using Alt+Tab. Now the edited geometry will appear in Houdini.
So you focus on modeling in both programs. You do not need to click a lot of buttons to import or export.
You also can quickly import existing geometry from ZBrush with "Z Import" tool.
For quick automatic retopology there is a tool "ZRemesher". You can do retopology automatically without unnecessary actions.
Z supports PolyPaint in both directions. In Houdini, the PolyPaint texture is stored in "Cd" point attribute.
Z works in Windows and GNU/Linux.
To install ZBrush in Linux use this link: appdb.winehq.org/objectManager.php?sClass=version&iId=36461