This is how I would approach the problem, although I’m sure there are plenty of different ways of doing this.
I would build the car using several different pieces.
The pieces would be things like front bumper, bonnet, door, side panel etc.
Each piece would have a number of meshes for damage level e.g. undamaged, medium damage, heavy damage.
Add a collider to each piece on the car, whenever something collides with enough force, change the mesh to the next level of damage.
If the piece gets hit and its on the “heavy damage” mesh, then detach the piece from the vehicle and give it it’s own rigidbody (enable the rigidbody) so that it will fall off and have physics.
Hopefully that helps to get you started
how would i create a mesh and how would i replace it with the damaged version?
– KK91020I see! Ok, so the same applies for the new "Articulated Bodies" that were added in unity 2020?
– GabsKapellmann