Useful commands for Pip (this is not usually pre-installed on Raspbian) are listed as follows:

• To install Pip or Python 3, use the sudoapt-get install python3-pip command
• Install the required package using sudo pip-3.2 install <packagename>
• Uninstall a particular package using sudo pip-3.2 uninstall<packagename>
• To find out the version of an installed package, use
  pip-3.2 freeze | grep <packagename>
• Install a specific package version using
  sudo pip-3.2 install <packagename>==<version>

For example, to check the version of Pi3D installed on your system, use
pip-3.2 freeze | grep pi3d.

To replace the installed version of Pi3D with Version 2.13, use
sudo pip-3.2 uninstall pi3d and sudo pip-3.2 install pi3d==2.13.