Welcome, Max
Imported heightmaps have to be georeferenced, but there's no limit to their resolution. For example, currently we use remapped data imported from heightfield with 1km resolution for oceans and 90m resolution for land. That's some 432,000 x 432,000 pixels for land data for whole Earth minus the oceans.
Outerra is not just a terrain engine, it's a planetary engine capable of displaying whole planet with complete level of detail from orbit to surface. Obviously, nobody would manage to paint the whole planet in reasonable time, so we are focusing also on procedural texturing and vegetation placement. The textures for terrain are generated on the fly, using terrain local information at pixel level, like elevation, slope and curvature, combining it with fractal data uniquely generated for the textured tile. In the near future we'll also support different climate & land types, matching terrain color of
Blue Marble data, with seamless transition to fractal-mixed terrain materials. That would mean for an artificial planet that you will be able to paint a map with colors representing land types like a desert, forest, steppes etc and the program will generate the detailed terrain using this map to guide its autogen process.
Current version has only a limited support for this, nevertheless everything is generated automatically, there's no external info except for the rough 90m elevation data.
In addition to the guided automatic generation there is also the possibility to use vector data for things like roads or generally where you do want to artificially alter the generated world. Vector data operations can modify terrain elevation and/or the generated textures as well, or remove/add trees etc.
Model importer supports only DDS textures, we do not want to waste time with additional formats now when there's much work everywhere, and anything can be converted anyway.
No support any 3rd party middleware yet, it will come later.
No voxel support.
Day & Night cycle is in there already, although it's not quite finished yet with respect to model lighting and the night sky.
Also the water is currently only a simple quiet plane, but we won't need DX11 for a better one.
Currently there are seas only at altitude zero, but there will be lakes that can be placed at any altitude using the vector data, i.e. once we import lake polygon definitions the lakes will appear inland.
