There is some way to save objects as cars and characters in a file separated of the scene file in games made in the game engine as well as is made in professional games?
Yes, using Python. There are several approaches to it: Saving the objects’ properties seperately or in bulk, when you make the objects register themselves in a GameLogic object. Search the forum - there are a few scripts out there for this… Explaining it in detail would be a little bit too much for here and I don’t have a suited file at hand.
As far as using TRUE external meshes it’s not really possible. With the blender modules from 2.23 or 2.25, it would have been possible to use python to hack in an object loader, unfortunately it would only work at the start of the scene. The latest build supposedly has some hacked blender python functions but I haven’t checked them out yet. External model support is something I have been wanting for a LONG time. Waaaaay too many meshes in crescent dawn = HUGE file size = LONG scene loading time + slow scene editing = BIG PAIN.
Oops! Must have forgotten my brain at work on that day! I thought you were talking about saving game entities, not the meshes in separate files - I don’t know what made me believe that! 