If you have the PC version of Tilt Brush too, you can open it up there and export it (it's a crossbuy app so you could use the Quest + Vridge if you had to)
It looks like you can import your projects into Unity, then export it from there (haven't tested)
Save the .TILT file by plugin in your Quest
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Then use something like adbLINK, navigate to your "Sketches" folder
And all your sketches will show up here:
Using this method, you're still only getting the .TILT file. If you want to convert it to FBX, you can use one of the python scripts here: https://github.com/googlevr/poly-toolkit-unity
Here is a full Tilt Brush guide that may be useful:
https://docs.google.com/document/d/11ZsHozYn9FnWG7y3s3WAyKIACfbfwb4PbaS8cZ_xjvo/preview#
The guide also references different config settings you can set
You can edit the config file on the Quest by editing this file
