Hi Graeme,
QuoteI downloaded the Zip folder and copied the extracted PD Space Guitar folder into the C:\Progam Files\Common Files\VST3 directory.
Please double check that the extracted folder name is "PD Space Guitar.vst3"
The extensions sometimes are hidden in the explorer view.
QuoteInside Cubase 11, I went through the usual specifications to tell Cubase which directory (folder) the new plugin was to be found
This is a bit strange: Cubase ( and other DAWs) automatically check this common folder.
Don't you have other plugins in C:\Progam Files\Common Files\VST3 ?
The VST3 system has a common installation path all VST3 hosts comply with. All your 64 bit VST3 plug-ins can be installed there.
The old 32 bit plugins also have a common folder too, you can read the info here:
See https://helpcenter.steinberg.de/hc/en-us/articles/115000177084-VST-plug-in-locations-on-Windows
Ok, now assuming that all the above is correct, and space guitar is in the common folder and restarted Cubase ( Cubase looks at startup in the common vst3 folders for updates ).
If the plugin still isn't visible, you can open the plugin manager in Cubase to see what is going on.
Devices > Plug-in ManagerPlease check if the plug is listed, the manufacturercode is PDL
You can also try a manual rescan there, ( option should be under under a cog wheel, if my info is right here)
Now, if the plugin is visible there, there should be some sort of status to it, showing that it usable or not.
If there is such a status, please tell what the status says.
The plugin is an audio effect, which you can select as an insert fx on any track.
-- Paul