is there a way to disable rendering preview of particle illusion?
Not at this time. Why would you want to disable it?
Do you mean as in After Effects where you can use the Caps Lock to disable rendering while tweaking parameters or repositioning an element without having to wait for a render? If so, it might be possible for us to add to the product - I’ll add that to the database as a future feature request.
Ah, I took the comment literally as a way of disabling the preview that shows in the render dialog (when rendering to file in PI). I didn’t think that they were asking about a way to disable rendering of particles in the Stage.
Hmmm … I guess that could be taken either way but the stop/play button at the bottom of the preview window would handle that case or they can just shrink the preview window so that playback is not visible - clarification from the OP would help.
Render window preview – when saving to file.