So I just had a small victory that I think others might benefit from. Maybe this has already been covered but I couldn't find it so here goes.
I was trying to figure out how to get all of my different materials out of my modeling program (cinema 4D) with no succes. I started digging around the forum for answers and realized I need an mtl file. Great, how do I get one of those...? More digging, the common answer was poseray. Great lets get poseray. Oh but I can't cause I use a mac! More digging and supposedly A C4D plugin I'd heard of before called riptide can export OBJ's with mtl files. After more frustrating trial and error I realize riptide (the free version) only works when running C4D in 32 bit mode. So finally after a frustrating afternoon, I've got textured OBJ's in terragen!
So if you use a mac and C4D and want textured OBJ's in terragen, get the free riptide plugin. And make sure you run your copy of C4D in 32 bit mode during export.
Hopefully this saved someone some time.
Try riptide pro, there is a free version but the pro version is on steroids.
http://skinprops.com/riptidepro.php
I also recommend taking a look at shadermap pro, as your material settings will not be handled by tg2 and your best off exporting a basic color texture and adding what you can, within the internal network node of tg2's material shaders.
http://shadermap.com/
Anim8or also exports mtl files.
what about blender (mac)?