I use the Python 2.7.3 that comes with Softimage 2015 SP1, but I do also have Python 2.7 installed on my system.
- Download and install PyQt.
- Set the PYTHONPATH environment variable to point to the location of PyQt4. You could do this in setenv.bat, or in the System environment variables. In my case, I set it in setenv.bat to point to C:\Python27\Lib\site-packages, which is where I installed PyQt.
- Download and install the PyQtForSoftimage addon.
- Check that everything is working. Open the Plug-in Manager, find PyQtForSoftimage, and run some of the examples.