Hi,
Funnily enough I got involved with TG because I was looking for something to create water and backdrops to use with renderings of my boat designs. At the time I was a boatbuilder and studying yacht design. I used Maxsurf and Microstation. I did all my rendering in Microstation at the time.
I do have TurboCAD 16 although not installed at the moment. I haven't used it for rendering or doing anything with materials, I was mainly using it for my house plans. I'll install it again and have a bit of a look at the texturing, but it sounds like some others have checked that out pretty well.
The file format you are going to have the most success with for TG is OBJ.
On a more general CAD note, I have never liked modelling with CG apps. I haven't done any modelling for a long time (aside from my house plans) but I really disliked polygonal modelling back in the day. I much prefer to use CAD. When I was doing yacht design I was all about doing it in 3D, especially because boats are complex shapes. I like the more precise approach of CAD software. There are much better CG type modellers now and not all CAD apps are good at 3D. I used to use Microstation because it had excellent 3D tools compared to AutoCAD, at the time anyway. I find TurboCAD pretty awkward for 3D. As with all software you don't always get on with everything :-). I think for certain types of modelling different approaches are better than others. If I was doing anything other than simple buildings or mechanical objects I would probably want to use CAD, but if I was doing more organic stuff I'd want a CG type modeller. It kind of depends on the way you think as well!
Regards,
Jo