This is a big necropost, to say the least, but, I have finally figured this out by myself and wrote a converter, as a C++ command line application.

https://github.com/tomysshadow/Groove-M ... -Converter

3DGM Model File Converter Scripted By TOMYSSHADOW Version 1.0 -------- This is a converter for 3DGM Model Files and related files found in .DCR and .GRV archives. It's written in JavaScript using DataStream.js . Simply open the included .htm file in a browser and click Browse, and find a .3GM (or .3...

Hi, this is my first post here! I've written a couple of converters for some formats before so I'm not a completely incompetent n00b (I would hope, anyway,) specifically the Acme3D IMG texture format, 3D Game Machine 3GM Model File format, Torque DIF format (what a nightmare) and the WBD archive for...