You can’t (yet? hint hint, devs…) send Midi from one plugin to another in Renoise.
…But you could load it in another host, and do [keyboard]->[other host with Cthulhu]->via some midi loopback or something->[Renoise]
It has been asked for quite a while.
So far the midi routing that was implemented was the vst fx alias in the instruments list.
I think that with a few slight code additions, the midi output in the instrument section can be expanded to allow output to other instrument slots instead of only to midi devices. This however would also mean that plugin instruments should be defined to accept midi input from more midi devices than the defined 4 main inputs or the dedicated midi in device. (or the track input)
I use the plugin version of Bidule in Renoise to host instruments I want to apply MIDI effects to.
Native MIDI plugin hosting would be ideal, but Bidule works quite well for my purposes.
One of my favorite features is Bidule’s ability to send MIDI to other instruments in Renoise.
Possible because Bidule comes with 32 Virtual MIDI ports.
Up to 512 parameters of plugins hosted within (each plugin version instance of) Bidule can be automated by Renoise.
Other options for allowing the use of MIDI plugins are MUX, and EnergyXT.
this is a problem i have had problems with for a looong time, too. here’s the solution i’ve come up with, just a couple of days ago:
use the MIDI mapping of renoise. use your midi keyboard and map every single key on your midi keyboard to a pattern sequence. this can easily be set up inside renoise midi mapper.
e.g. pattern 0 = chord 1 (on the first row), pattern 1 = chord 2 (on the first row). basically, you play one chord at the first row of a pattern, and any time you hit the midi keyboard’s key, renoise will jump to the according pattern in the sequence and play exactly that chord, which is associated to that pattern.
now, this way you can easily play one-chord notes on your midi keyboard. now, the cool thing is, when you’re running renoise twice (for example, i run 32-bit renoise and 64-bit renoise at the same time), you can use your “chord template” and use a “external midi instrument” which is sending midi data to “renoise midi in” so the midi data is sent to the other renoise instance, which is actually your real song. this way, you can always use the same chords template file, and in your actual song (which is opened in the second renoise instance), there you can easily swap synths, change transpose, and easily record the chords into the pattern …
this works great, no need for any plugins.
before i’ve discovered this solution, i used cubase’s “chorder” plugin and routed that between virtual midi devices into renoise … but as you can see above, you can do all of that with plain renoise.
alternatively, you might want to dig into “scale finder” tool from the renoise tools page. it’s great, however it is missing the bass notes as well as the chord inversions. - this can easily be done with the solution described above, though.