DSP Robotics Support

Midi topic is rather foreign to me, so apologies for eventual confusions.
What I'd like to achieve is following.

I have a vst effect with midi control/keys within it. This vst effect operates on audio content.

What I need to do, is to have a way, that when I press the midi note (or chord) - midi volume of these notes fades in slowly (few to 40 seconds or more regulation) to maximum, and when I release it - midi volume slowly fades out to zero (the same long times). So this should be valid to individual midi notes (but can be the same timing for all notes; it's just this is not about fade in/out on midi track, but on midi notes). Plus it would be good then to have some control over the fade curves (linear mixing will not produce smooth output)

So I guess, in hosts like reaper - it would go like this:
midi keys -> midi effect (fade in/out) -> vsti plugin that outputs processed audio.

1) Is this doable anyway? (what plugins would do this in hosts like reaper?)
2) Is this doable in Flowstone? (how?)

what do you exactly mean by fade in / fade out?

Fade in: when pressing the midi key(s) - volume of pressed note(s) goes from zero to maximum.
Fade out: when releasing midi key(s) - - volume of that note(s) goes from maximum to zero.
In the meantime it keeps the maximum volume.
(everything else, i.e. sonically - happens in audio processed by vst plugin - like waves morphoder).

Fade n/out time: adjustable, between few seconds to about a minute or more
Fade in/out curve: adjustable, because linear will not fit here.

It's not a thing for manual corrections on midi track in DAW; too messy. Alternative would be some script for adding fade in/out curves to "volume in time" of notes according to some templates I guess, but no luck with finding it (in reaper) yet.

The Midi protocol doesn't support note volume messages, AFAIK. Volume changes are per channel, affecting all notes on a channel at once. Only chance would be to roll your own messages (eg. using polyphonic aftertouch), but the Effect plugin which receives this message has to know what this message means, so you have to build this custom, too. At that point the whole thing is useless, because it would be much easier to build the same functionality into the audio effect instead of messing around with an additional midi plugin. BTW: FS doesn't support Midi-Only-Plugins...

should be no problem with cubase note expression maps

To particular example, I can't do reverse engineering on waves morphoder because I'm not sure what I'm looking at (but if you know how to replicate "thalamus" preset - I would be interested; it's a very specific combination with audio I use). Generally volume control could be common for all notes on track; notes go in harmonic chords in these projects. So I guess if there are other fades, it would just involve 2-3 paralel tracks.

"cubase note expression maps" - how old cubase version can it be?

As mentioned before, Midi protocol has no "volume modulation" on per note basis. There is "note on" with pitch and velocity and "note-off" with pitch and velocity. There exists per-note aftertouch if I recall correctly, which you can use to modulate notes while pressed. However, flowstone can't interpret those on its own (= there is no "per note aftertouch" output on midi-to-poly module). You can possibly write a ruby module, that reads per-note-aftertouch messages and sends them to coresponding voices in poly. Frankly, I have no Idea how to do that.

Do the fade-in/out lengths and curves need to be adjustable per-note and on-fly via midi? If answer to both of those is "no", you can probably go with ASR envelope (attack, sustain, release). and possibly automate attack and release lengths/curves via midi CC controller, making it adjustable on-fly.

Surely by "volume" he simply means velocity. Velocity is very commonly used to control note volume.

As KG mentioned, ASR envelope... this should be extremely simple with that!

Or detect incoming midi note-on and use that to trigger the slide component then attach to midi MIDI CC 7 (Volume).

In Reaper, I see something like Rea Mici Control, which allows to automate selected CC lanes. If I understand it correctly, it takes messages from physical controller connected to PC, and transforms them according to - for example, automation wirings. As far I can see - it works.

So this leads me to a question. Can I capture that way - incoming notes from hardware (or midi track) and send to vsti instrument in a desired manner? (for example, manipulating selected CCs for individual notes - combined with a sort of filters or lists?).

[One thing I have not figured out yet is, whether there is something in Reaper specifically - to apply custom fade in/out curves to CC lanes to individual notes there]

ASR envelope is within VSTi if I understand, thus - may not work as expected.

Sorry for confusion, but this topic generally is not from my area.