Takes!

[Odin]

Takes are a very powerful and unique concept in Reaper.
With them we can create different versions of MIDI-clips and have them always available within the same item! No copying, no moving around, no exchanging, to test different melodies or variations. Just right click on a clip and choose the different take.
So i'd recommend, to open clips for editing as copies. Opening as a copy and saving the changes, creates a new take.

Example:
MIDI-clips on different tracks feed a track with a VSTi (+FXs).

You want to free up CPU, but have the MIDI data available for later editing without moving clips into subfolders or other administrative tasks.

Solution:
- Drag the MIDI clip to the track with the VSTi.
- Right click the clip and choose APPLY FX AS A NEW TAKE (this renders the sound and the resulting wav-file is attached to the MIDI-clip as a new TAKE).
- Drag the clip (it now consists of the original MIDI-clip as take 1 and as the audio-file as take 2) back on the original MIDI track.
- Now you can switch off FX on the VSTi-track.

So you have the MIDI rendered to audio, and if you want to switch back to MIDI for editing, simply right click the item and select the older (MIDI) take! Incredible.

If the rendered FX becomes cut off at the end of the clip, because the MIDI-clip ends, before the audio tail has faded out (i.e. because of a delay), this is also no problem for Reaper: before the render, simply extend the MIDI-clip by dragging the end to the right and choose APPLY FX AS A NEW TAKE afterwards.