So it happened a few times to me that i render a song to disk, and there’s several seconds of silence at the end of the resulting .wav file - seems the disk rendering process IGNORES the ZT00 commands and goes on towards the end of the last pattern …or the entire orderlist (haven’t tested) - but this is definitely a nuisance, at least in this case –
Solution: Listen to the song or open it in some program before uploading
But really, I always listen to the result of a render to make sure it came out okay, as well as open it in Goldwave to save the mp3 version. I would never just blindly upload a song after render.
Regarding the functionality that you crave for :Consider the ZT command as nothing more than a deprecated feature to provide for older xm/it/mod import formats because in most of those trackers, you could not change the pattern size of individual patterns.
Besides the above fact, consider it also a useful aid during the production process to quickly set a boundary so that you can prevent Renoise from continuing beyond a specific moment.
The render feature in Renoise depends on the range that is selected to be rendered from the sequencer.
“Entire song” means the complete sequence range in the sequencer, nothing less. If you want less, then specify so in the render dialog or limit the size of the last pattern up to the row where you want to have it played, since you can alter the pattern size in Renoise.