Miguel Ángel sent me a note about GTO, a (from their web) "open source file format designed for computer graphics. It was developed by Tweak Films to serve as the core storage format for our geometry and rendering pipeline. GTO is used by VFX and animation facilities, post-houses, and game developers for a wide variety of applications. It's small size and versatility make it useful for animation, modeling, particle dynamics and 3D paint. It can be used to replace file formats such as PDB/PDC, obj, and binary RIB."
According to Muguel Ángel, it is based on ILM´s Zeno underlying principles, and even some developers have worked in Zeno.
Miguel Ángel also mentions Tweak´s revision software, RV, which is now integrated in Shotgun, and the impressive professional history of Tweak films founders, most of them TDs iat ILM, Weta or DD.
Thanks as always, Miguel Ángel