I see that rhiexec is gone now, and am wondering what the procedure is for installing a plugin in Rhino 6. In the SDK documentation I see something called CRhinoInstallPlugin::Install. Are we meant to install plugins programmatically now?
Okay, that page seems to say that the choice is made automatically (by rhiexec), so I will just forge ahead and try it, and see if it ends up in the right place. Thanks for your help.
You should not need to find rhiexec on the system by full path. Rhino registers the .RHI file extension, so you can simply shell-execute the .RHI to do the installation.