Thank you. Your discussion on the forum here is also very helpful. I think for my purpose loading my volume property file (.vp) is sufficient, and I have managed to add the following code to my .slicerrc.py so that my .vp file is loaded automatically:
vp_file = '/path/to/myVolumeProperty.vp'
volRenLogic = slicer.modules.volumerendering.logic()
volRenLogic.AddVolumePropertyFromFile(vp_file)
However, I now still have to go to “Inputs” section in the volume rendering module to select this volume property every time. Do you know how I can set it as the default volume property in .slicerrc.py? I am really unfamiliar with writing python scripts for slicer and have found it very difficult to find the write function to use, so your help will be very much appreciated!