Pivy is a needed by several modules to access the 3D view of FreeCAD. optional, but needed by several modules of FreeCAD: Draft, Arch.- the PyQt4 API Reference on sourceforge.
Some pyQt4 tutorials (including how to build interfaces with Qt Designer to use with python): setToolTip ( u "Coordinate placement Axis Y." ) # PySide Additional documentation Once it is installed, you can check that everything is working by typing in FreeCAD python console: See Install dependencies for more information. PyQt on Mac can be installed via homebrew or port. You'll need to install the Qt and SIP libraries before installing PySide (to be documented). The necessary dependencies (Qt and SIP) will be taken care of automatically.
On Debian/Ubuntu systems, the package name is generally python-PySide, while on RPM-based systems it is named pyside. The simplest way to install PySide is through your distribution's package manager. Note: FreeCAD progressively moved away from PyQt after version 0.13, in favour of PySide, which does exactly the same job but has a license (LGPL) more compatible with FreeCAD. If those modules (Draft, Arch, etc) are enabled after FreeCAD is installed, it means PySide (previously PyQt) is already there, and you don't need to do anything more. It is already bundled in the windows verison of FreeCAD, and is usually installed automatically by FreeCAD on Linux, when installing from official repositories. PySide (previously PyQt) is required by several modules of FreeCAD to access FreeCAD's Qt interface. optional, but needed by several modules: Draft, Arch, Ship, Plot, OpenSCAD, Spreadsheet.
This page lists several additional python modules or other pieces of software that can be downloaded freely from the internet, and add functionality to your FreeCAD installation.