I want to use really extreamly complex model in game, currently using cryengine, I can use objects with -64k faces. I am forced to break up my super complex models and spawn them in the engine. I am making a space sim like Kerbal space program but in Cryengine. I have had collision issues. My planet model with planetary terrain is really heavy in 3ds max. but in CE3 it doesnt effect fps. I have gravity etc.. Beside that this model issue. The planetary model is buggy (as it is in parts) I had to place each part in game so that is why it is buggy. I was wondering is there a engine that can use not just something like a cry file (engine based mesh format) and just use directly a 3DS or OBJ, FBX file.

example: lets say cryengine can use 3ds file format. I would be able to use the 3ds model in game.

Unity doesn't support the feature you ask for, but it kinda support your scenario.

If you try to import >64K tri mesh it will split it, but as submeshes inside of a single game object, so you'll place a single game object and won't have to manage the dozen of subobjects yourself.

You're still going to need to apply the shader to each submesh however.

{Interested}

So it automatically splits >64k models. Correct?

Yup; i imported much larger objects and ended up with a single (empty) gameobject containing many meshes (1 per 32 or 64K i can't remember vertices).

Now it won't allow arbitrary vertice amount (it will crash if you really give it something crazy as the editor isn't 64 bit) but it will go way way beyond 64K, i imported 1+mil meshes easy, it "did" crash on importing a 36mil vert mesh however for me.