LinPlug Octopus - Manual (Page 29)

Release
The Release control determines the way that envelope releases are
handled. Note that if the Free-Run control (see below) is switched ON, the
Release control has no effect. If the Release control is switched ON then
when a MIDI Note Off message is received the envelope moves to the loop
end point and then moves through the release portion of the envelope.
When the Release control is switched OFF then the envelope stops at the
position it was when it received the message if its an Amplitude envelope,
otherwise it just remains in its loop (if there are loop points set). The release
portion of the envelope is not used. The OFF setting of the Release control
is useful for creating LFO effects although you are free to use it in other
ways as well.
Free-Run
The setting of the Free-Run control determines which portions of the
envelope play back when the instrument is triggered. When the Free-Run
control is switched OFF the envelope begins with the attack portion,
proceeds through the loop portion, and then, depending on the setting of
the Release control (see above), either moves through the release portion
or stops. When the Free-Run control is switched ON the envelope begins at
a random point between the Loop Start point and the Loop End point.
Manual 27