File format I currently support for importing meshes is collada (.dae). Should there be any problem with that, any reasonable format from those can be supported too (if there won’t major be problems with it)
http://assimp.sourceforge.net/main_features_formats.html
All kind of rigging is done in editor which is included in download. Only thing imported are meshes themselves. Anything larger than a simple frigate was unmanageable using 3ds max helpers, hierarchies, naming conventions and hand written text files, so I decided to make it this way. It also doesn’t limit to using specific modeling software.
All models in videos are less than 10K triangles, though that is hardly limit. As it is RTS, I expect models to be around this for average ship (there is also little reason to have ridiculous amount of geometry detail anyway). As for textures, jpg, png and dds are currently supported, but again anything from this list can be added (if there is any good reason for that)
http://freeimage.sourceforge.net/features.html
Though using lossless formats (like png) is highly recommended. There is option to compress texture on GPU, but it doesn’t look all that good for e.g. shininess map.
It is based on OpenGL 3.2 (is it even a factor in your decision? I dunno, maybe there are some deal-breaking differences I’m not aware of). I use AngelScript for scripting. It has C/C++ syntax. There is also documentation for all available stuff you can use on main page (it is just most basic stuff right now, anything that will be needed will be added)
As for content, I take anything. If you want to make a Freelancer ‘mod’, great, go ahead! If you want do do your own original stuff, great, go ahead! If you want to cooperate with me on my vision of ‘vanilla’ content, even better. If you can do sounds, animated sprites for particle systems or just asteroids, there is always short supply of those. Or if want just to balance things, there is some Star Wars mod-in-progress that you can balance. You know, brand new game - there is shortage of everything