First Pic : http://www.beamng.com/threads/splitable-covet.21931/ Second Pic : Usually a glitch, but you can get the effect o the tire by puncturing them (Drive on spiky objects, thin metal bars, etc)
The pic with the nascar is a WIP vehicle, however you can get that type of damage with the pigeon, and a few bumpers and carbon fiber hoods in game, it you crash hard enough it just makes that part of the vehicle disappear to give the impression it broke off, (doesn't work on all vehicles).
Iv'e only noticed it on the pigeon, the bumpers and carbon fiber hoods on the covet and 200bx. The trailers also get this kind of damage
I recall a dev saying somewhere that it's the game's way of interpreting a beam breaking in a mesh-ed object. These breakages occur on brittle parts (or in the case of the split-able covet, along predefined points in the body where breakages are allowed to occur) in extreme circumstances. Since plastic, carbon fiber, and fiberglass don't bend so much as break in heavy impacts, the node beam structure can only interpret a "break" in these parts by breaking the beam and removing the visible mesh that once occupied the area that the beam was in. IIRC it is/was supposed to be a temporary solution for brittle materials, but I'm not sure whether or not they will ever be able to replace it with anything better than what we have now.
Pic 1: Spitable covet mod, I think it's nearly outdated though, hasn't been updated in a while Pic 2: That's a WIP, also, what you have circled is a glitch that isn't supposed to happen
that can be used to prevent spikes from happening, like the ambulance. so it is supposed to happen to prevent spikes (i think)
Its not a glitch!! Its called mesh breaking and you can enable/disable in beams section. Ill edit this with the parameter edit to create that covet damage, you would have to edit the values of certain beams in the body jbeam to allow it break, that way the car can split in two. as for mesh breaking: put this at the beginning of the beams you want the mesh to break, like the fender shape section, but NOT the rigidfiers Code: {"disableMeshBreaking":false}, then put this where you want mesh breaking to end Code: {"disableMeshBreaking":true}, finally, edit the beam strength values to allow those beams to break
It appears you didnt edit beam strength. The one thats one line above, remove "FLT_MAX" and replace it with a number like 12000(that could be wayyy off, just guessing), edit that number up or down to whatever works, and make sure you close the mesh breaking wherever in the beams section you want to end mesh breaking.