It's pretty easy to do, if you have a computer sequencer with a graphic editor.
Say you wanna make it sound like an acoustic strumming a four-note C-major chord (bass note=c, bottom chord note=g, middle chord note=c, top chord note=e). This works for any chord, I'm just giving an example with this one. You play the chord flat into your computer sequencer, so that all the notes start on exactly the same beat. THEN, after playing, go into your graphics' editor window. To simulate the "guitar strum", pull the middle chord note back a little ways so that it starts a little before the rest of the chord. Not much. Then, pull the bottom chord note back so that it starts a little before the middle chord note, maybe the same distance away from the middle chord note as the middle chord note is from the top and bottom notes. Now, you have your bass note and your top chord note starting on the beat, but you have the bottom chord note and the middle starting a little before it, so that you hear the bottom chord note first, then the middle chord, then the rest, with just enough space between these three items so that it sounds like you've strummed a pick across a guitar. But we're not done yet! Now, go into your Velocity Editor on your sequencer. Make the bass note and top chord note the loudest, the ones that actually fall on the beat. The middle chord note should be made a little softer. And the bottom chord note should be made even a little softer than that. Now, when you play back the chord, you hear the strum that is fully realized on the beat, just like a real guitar! You can spread out the space between the middle/bottom chord notes to get a longer strum that still falls on the beat, or add more notes for a strum that goes farther along the guitar neck. You have to experiment. I've done this for years with
acoustic guitar keyboard patches. Hope this helps!
