I always thought that specific send automation option was for "the other way round". Normally, this is what a plugin does (from the specs manual):
Parameters are the individual parameter settings the user can adjust.
A VST host can automate these parameters.
Programs are a complete set of parameters that refer to the current state of the plug-in.
Banks are a collection of Program objects.
From the host application’s point of view, a VST Plug-In is a black box with an arbitrary number of
inputs, outputs, and associated parameters. The Host needs no knowledge of the plug-in process to
be able to use it.
The plug-in process can use whatever parameters it wishes, internally to the process, but it can
choose to allow the changes to user parameters to be automated by the host, if the host application
wishes to do so.
...In this case the parameter directly reflects the ‘value’ used in our processing method. When the
user ‘turns the dial’ on a generic plug interface it is this value that gets swept between 0.0 & 1.0
as the
setParameter()
function gets called. If you want a different relationship between the
parameters that are automated by the host and what is actually used in your processing method,
then that’s up to you to do the mapping.
(Flowstone does not support this mapping. We are on the "direct" path.)
Sraight forward. We set parameters, but also allow the host to send us a value that we then use for our knob or whatever else. That would be "receive".
So "send automation" in my mind is meant to control other things
that are outside of the plugin, maybe a DAWs track automation. Something like this. But I never bothered with it or test anything.
Btw., just by reading through the specs I found something I wasn't aware about yet (as sad as it is). We all name our presets properly, at latest after you read Spogg's preset guide. Now, the preset strings are special! Didn't know that! Again, from the specs manual, regarding parameter's name, display and label:
Please be aware that the string lengths supported by the default VST interface are normally
limited to 24 characters. If you copy too much data into the buffers provided, you will break the
host application. Don’t do it.
The default interface is what the DAW uses if it can't open the GUI (or if there is no GUI defined). In Reaper, you can switch to the default interface at any time by the click of a button.
In other words: Using more than 24 chars is undefined and may or may not work.