Modeling use MilkShape 3D.
It's only 19.99 USD to buy it, the trial lasts 30 days
MS3D comes with 2 DTS exporters, one is the Torque Game Engine DTS exporter, and the other is Torque Game Engine DTS Plus exporter that has more features than the original DTS exporter, i use the Plus one, but you can use either one you want