Is there any chance one could add a tickbox here for “Add resultant WAV to Instrument slot” ? 
Maybe generate a entirely new project of all the stems, rather than adding to the existing one? Samples added, patterns as notes within instrument is set to save separately, each triggered through the song (so either at the very start or start of each pattern.) Pattern sequence (sizes, bpm etc) would follow that of the original. In fact can you just clear instrument, pattern and automation data maybe? Is this all (including Render) available to the API for it to be done through scripting?
Yup. Look for renoise.song():render()
Cool. Good idea for a Tool then. Got so much other ish going on at the moment I’ve not even looked into the API yet though. One day…
esa - any chance you’re asking for a similar thing to me? What you suggest is one of a few possible solutions to my problem: I can’t render a multi-pattern selection to a sample/instrument, so either a ‘Render Pattern Selection To Wav’ option needs to be added in the sequence list OR the option to drop the rendered output into a sample needs to be added in the Render To Disk dialogue, as you suggest. My request thread sort of ground to a halt, though
A reiteration of the problem: Render Selection To Sample won’t span multiple patterns and is useless for recording lineIn audio from hardware synths, especially if there are reverb/delay tails that extend beyond a single pattern. Having to merge or temporarily expand patterns in order to capture this (usually on a trial/error basis, as you don’t know quite how long it’ll need to be), loads of times throughout one composition, is a tremendous cumulative pain in the arse.
(Edit: and yes, it’s a prime candidate for an API tool, but it’s a tiny thing that SHOULD be native, bringing Renoise yet further into line with most other music software. Ableton Live does this in a brilliantly transparent and hassle-free way - a good role model, perhaps)
Syphus: I believe there is more than a passing resemblance to what you’re after. Especially the “spanning multiple patterns” part, especially with outboard hardware with long releases.
And while someone might be able to make it with the API, it would be absolutely lovely of Renoise to have it native