Topic title says it all. Ableton Live has it and it saves me alot of time. Please bring it to Renoise.
You can achieve that same effect by putting a Stereo Expander on the master channel, with the Expand parameter set to Mono and the Mono Mix parameter set to L+R.
Yeah, but then I will have to keep 2 versions of every file in order to quickly change between stereo and mono, and update any changes I do to both files (songs). I can’t see whyit is so problematic to implement such a feature, I asked for it 5 years ago too, and got the same answer. Besides, stereo files are twice as big as mono files, which is noticeable on my 128GB SSD. Thanks for the help, anyway 
I can’t see how you would need this so much? When you have a rendered sample you have the same options for converting to mono… Maybe only a ‘batch render samples to mono’ option would be nice, but… not really Renoise’s task imo.
By the same argument we could say Renoise doesn’t need an integrated Sample Editor at all!! 
I think every DAW I’ve used have all had a mono option in their export/render settings, could come in handy in certain tasks I guess.
Too late.
You must’ve never used Renoise!
What is this Renoise you speak of.
Excuse me? you can toggle on/off the stereo expander.
But are there specific tracks you want to render to mono or just the whole song?
It looks peanuts to write a tool where you can perform these actions with one click. (the tool adds a stereo expander, sets it then renders the specific track and removes it again after being done)
I don’t see why OP’s render to mono is a bad idea, I think it’s great addition to Renoise. There should be an option to render tracks to mono (mix l/r), stereo, and option to split stereo tracks to two mono ones on main render dialog. It can save a lot of time when you need all mono tracks in your project. And yes, you could use Stereo Expander, but that render would again give you stereo wave at the end, and sometimes you just need mono wave.
Thanks for replys! I will put a stereo expander on stand by, then. Still, I don’t see why it is so anti-Renoise to have mono render, but I won’t ask again.
Should definitely have a mono render. The Stereo-expander approach will still result in a stereo (duplicate mono) file, taking up twice the space.
Mono render could also be useful for sound effects work. And track/stem transfer I presume.
Well, there is still this tool:
http://www.renoise.com/tools/batch-convert-stereo-to-mono
Some hints to additional code to make it render selections…
renoise.song():render([options,] filename, rendering_done_callback)
-> [boolean, error_message]
– See renoise.song():render(). Returns true while rendering is in progress.
renoise.song().rendering
-> [read-only, boolean]
– See renoise.song():render(). Returns the current render progress amount.
renoise.song().rendering_progress
-> [read-only, number, 0-1.0]