I'm developing a simple racing car game. I'm wondering what is the best approach to manage visually car destruction. For instance: i think one option (expensive) is to build car 3d model with 'separate' mesh, each for any component (bump, door, glass) and relative cooliders.. Other options ? Thanks
If you just want bumps and scratches, you can do things like use effects and deform the vehicle mesh and you wouldn't need a large collection of objects.
Assuming you want to have bits fly off in a super realistic fashion and have it look awesome, then I think the easiest way is to do what you already suggested. Have a collection of objects that can detach away from the main body and be destroyed afterwards. Most 3D models you can download will come as a collection of parts anyway, though.
The only other approach I can think of is to make your own procedural destruction system, similar to the one CryEngine 3 uses. That would be a lot more work though.