s&box

Live tuning lab in the demo scene. A small T chip sits top-left from the moment you spawn; press T to expand it into the full lab: sliders for grip, drive torque, suspension stiffness, damping, travel, and brake force, plus assist presets (Casual / Sport / Sim), tire compounds (Stock / Street / Sport / Offroad), and a reset-to-stock button. Every change applies to the running car instantly, and the camera hands you the cursor while it is open.
Switch between the four cars with [ and ] (d-pad left/right on gamepad), same bindings as Vehicle Prototyping. The camera, your controls, and the tuning lab all follow along, and a key legend up top-right reminds you.
Modeled blockout cars. All four roster cars now spawn with stylized low-poly bodies and real cylindrical tires with rims instead of boxes and spheres. Visual only: the physics under them is unchanged.
The tuning lab and the cursor-yield camera seam double as working examples for your own UI.

Demo pad grown from about 200 m to about 1 km across, so you stop reaching the edge in seconds. Driving off the far edge still respawns the car.

Wheels now spin the correct way while driving (they rolled backwards before).
A car left near a stop now actually stops. No more endless creep with spinning wheels and skid noise unless you halted perfectly.
The camera's cursor-yield hook now survives hotloading. If you wire CursorModalOpen from your own UI and hotload mid-session, the kit recovers instead of throwing on the next play.

The demo keybinds use "Tune", "CyclePrev", and "CycleNext" input actions; consumer projects add them in their input settings, the README shows the exact entries.

Parked demo cars now hold the handbrake and ignore your input devices from the moment they spawn. Previously there was a one-tick window where a parked car could read a live gamepad, and a resting trigger with a little drift reads as brake, which at a standstill engages reverse. That is why the Go-Kart could crawl backwards out of spawn on its own.
Parked cars can no longer be nudged off their spawn marks by device noise or spawn settle, they stay put until the camera switches to them.

The active car (the one the camera follows) still reads your devices directly by design. If your gamepad has heavy trigger drift the active car can creep at a standstill, unplug the pad or recalibrate if you see it.

First public release of the Vehicle Physics Kit, the raycast-wheel stack that powers Vehicle Prototyping.
Contact-normal suspension, slip-curve tires with a friction ellipse, and a full drivetrain with auto-clutch plus auto and sequential shifting.
Per-car assist levels (Casual, Sport, Sim), spring-arm chase camera with orbit and scroll zoom, and placeholder engine and skid audio.
Four ready-to-drive roster cars (hatch, coupe, kart, pickup) on primitive blockout bodies, no art needed to start driving.
A bundled demo scene: install the kit, open vehiclephysics_demo, press play.
Seams for making it yours: CustomBodyBuilder swaps in your own car models, InputOverride lets an AI or replay drive, CursorModalOpen plays nice with your UI.
Full README with quickstart, API tour, seam list and required input actions.

Kart stuck-turn fix ported from upstream Vehicle Prototyping: cap-aware drive torque rolloff plus a Casual traction control floor relaxation, so turning hard under power no longer locks you into the turn.
Demo quality of life: only the car the camera follows listens to your keys (one W press no longer launches the whole row), and cars driven off the pad edge respawn on their marks instead of falling forever.

The cars are ugly boxes on purpose. This is a physics library, your game brings the art.
First generation release: the core physics is proven in a shipped game, but the API surface may still move.