The MODULATION assignments section allows you to override and remap the standard MIDI messages used by the Modulation Matrix sources in Omnisphere. Simply select the drop-down menu next to one of the fourteen modulation types and a pop up will appear that says “Move MIDI Controller” Then on your MIDI controller move the knob, slider or wheel that you wish to use to remap to that Modulation source.

The ‘User CC’ Modulation source is particularly useful for adding an additional, non-standard MIDI Controller into the Omnisphere Modulation Matrix – without disrupting any of the standard assignments.