It would be very useful if the BIAB plug-in could stay synced to Pro Tools when a song has a LOT of tempo changes. I know I can add tempo changes in BIAB at specific bars, but when there are a lot of tempo changes, this just takes too much time. This comes up if whenever you have a song you recorded in PT rubato, and afterwards place barlines at appropriate places by using a series of tempo changes. This method can produce maybe 50 tempo changes in a long song. It's impractical to enter all this into BIAB, plus BIAB only takes whole numbers for tempos, not something like 122.4536 BPM.

Not having this feature means that BIAB can't be used with any song that wasn't recorded to a click.

If anyone has a workaround, I'd love to hear it. Thanks!

Thanks ! I have been saying that for years.
They said it was going to be added next year to playback the generated tracks to the DAW tempo changes from within the plug-in, I don't know if that meant December release or mid 2021 ???
You can generate it with ACID info (in Preferences) meaning when you drag it into the DAW it will fit to the tempo map of the DAW if it supports ACID, or some will let you set the bpm of the file then fit it to the Tempo map. Pro Tools will do this, but the plug-in won't play the track back in sync to the DAW from within the plug-in until you drag it into the DAW.
Another feature that should be added some time is being able to drag a midi into the plug-in from the DAW that has the tempo map, the plug-in will then set the tempo changes in the plug-in also, thus it will render the the track already tempo mapped.
The thing is as you say the SGU format only stores whole numbers and not decimal points for the tempo map so if it could allow that or have another save format like RealBand that has decimal point tempos.

Adding ACID information overcomes that, allowing you to generate a single tempo in BIAB (e.g, 120) and dragging that into your DAW that will then change it to the DAW’s tempo map including floating point numbers like 123.56
Other solutions seem much harder than that, including entering the same tempo change information into the plugin as your DAW.

Further down the wishing well there is
A VST to send Tempo/Play/Stop/Loop/Continue to main Biab app from DAW

Peter it's 3 years later.
Not being able to play back in sync to the DAW's tempo map and dragging tracks from the Plugin into the DAW defeats the whole purpose of the Plugin as you may as well use Biab.
It has already been mentioned above to be able to drag a DAW midi track in the Plugin to get the tempo map.
But you have dllelastiquePro3.dll why are you not using it.
I showed you Reaper as a Rewire slave adjust it's decimal tempo map on the fly with eleastique to sync with Biab solid tempo.
The only time you responded was when I showed the Rewire VST working with RealBand and you said you would implement it.

I post so many things that so many other companies use but they seem to get totally ignored without a whisper of response and people wonder why I get stressed and say I should not give you a hard time because you are "old". I gave you respect by staying the long run since I first purchased in 2009, it had so many issues but I did not give up and leave and say "stuff em who needs this". How many posts has Beej above made and you blow it off, there are so many like this. Intelligent users that are just dismissed.
Peter, you are not working with the Plugin every day, for you to dismiss things so easy and say as much as "I'm happy with it, stuff them they can make do with how it is". "Adding ACID information overcomes that" honestly ask yourself. You are way out of touch !
Why don't you take a bit of pride in what you make without going off half cocked and expecting users to make do with workarounds as you think it's OK. Users say I should give respect, but I never got respect from all the time I've spent here and all the information I've posted. It's blatantly ignored as ravings of a madman.

You rely too much on users that are not up on things and will follow your lead and worship that. That's what your loyal followers have done over the years, got rid of intelligent users asking for change hence it being behind. Protectionism.

Please to God, see some light, I really pray for a miracle of enlightenment.

The Plugin actually looks like a serious studio app but falls short with it's rear end giving it so many limitations.

That's exactly the same problem I have too. Unfortunately no solution in sight, other than tempo equalizing the originally recorded track to a constant tempo, e.g. by using the ACW tool in the BiaB standalone.
Not really a good solution.
I am repeating myself, but the BB plugin should follow the DAW tempo somehow!

There has been no new response to this issue so I'm looking into creating a VST that will read the current track data in the main Biab and transfer that to the VST (same as I can do in Reaper), so the VST will be playing the source track sections back in sync to the DAW tempo map.
As you drag it will render the sections to wav. This should work with Midi also.

Doesn’t this work already by saving the file in BiaB, and including acid information? And then dragging to ProTools? proTools (and many daws, will stretch the wav file to the tempo map).

BiaB doesn’t yet support floating tempos, and every possible time signature (e.g. 11/8). But that is planned. When that is done, better sync options for BiaB and the plug-in should be available.

The VST just needs to use elastique to sync playback as if it's playing back direct it will use eleastique to change pitch and tempo in realtime.