I guess you do this in CAL.
Copy/paste the code below into notepad, and save it as RANDDEL.CAL, select your track, use Process->Run CAL and navigate to the file you've saved.
Note this will
delete random notes, so make a copy of your original track before running it.
;
;Delete random notes
;The higher the strength, the more notes are deleted
;
(do
(int iStrength 1)
(getInt iStrength "Strength 0 - 10 :" 0 10)
(forEachEvent
(if (== Event.Kind NOTE)
(do
(if (<= (random iStrength 100) (* iStrength 10))
(do
(delete)
)
)
)
)
)
)
I guess, you could change the (delete) to change velocity instead, or even change the first if statement to narrow the selection down to certain notes (e.g. hi-hat).
Here's a good guide on CAL:
http://members.ziggo.nl/t.valkenburgh/Cakewalk%20Application%20Language%20Programming%20Guide.pdf Mark.