i’m no programmer, last time i’ve touched c++ was over 10 years ago in high school. I’m a 3D artist but i’ve been giving a go at chaos vehicles myself in the past few months. I’ve been digging a bit and as far as i understand it the issue relies in the fact that there is no clutch simulation and that the engine RPM is derived from the speed of the wheels - see Transmission.GetEngineRPMFromWheelRPM(WheelRPM) in ChaosWheeledVehicleMovementComponent.cpp i believe.
My understanding is that this is a cheap and quick way to make the car go vroom but at the same time removes entirely the possibility to drift the car or use sliding in any meaningful manner.
My suspicion is that Epic, some dev or anyone with the skills has to modify the source code of chaos vehicles in order to add a clutch and a proper engine RPM simulation. That function is named as if the wheels have a force and their rotation determines the engine RPM so as soon as you start drifting, the wheels slow down, and so the engine, which means less power output, less speed and you slow down to a crawl. RPM dies mid air too because i think the wheels have no surface to have contact with so no force is actually applied and thus they don’t spin. same goes if you are going very fast and suddenly hit the brakes a bit when steering and end up in a spin: the RPMs go negative as does your speed because of the same reason.
I asked around at work (we’re using UE4) and seems like the best way to go is to clone the chaos vehicles plugin so not to edit the original one, add a clutch simulation, add proper engine rpm simulation and set the transmission of forces as it’s supposed to be: engine-drivetrain-wheels (because it seems it’s the opposite of what it’s supposed to be, the way it’s coded right now), and expose a whole bunch of functions and variables to blueprint which are quite vital to prototype a sim racing game with chaos but that are currently not available in the official build.
I wrote to Paulo Souza (he made a video on chaos vehicles on the UE YouTube channel recently) and mentioned this issue, so hopefully we’ll get someone from Epic fixing this or some other dev coming up with a solution, i don’t have enough coding knowledge myself sadly.