Vehicle Physics Kit
Raycast-wheel vehicle physics for s&box: slip-curve tires, full drivetrain, assists and a chase camera. No art required.
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About This Package
A raycast-wheel vehicle stack for s&box, extracted from our released game Vehicle Prototyping. This is the exact code that game runs: contact-normal suspension, slip-curve tires with a friction ellipse, a full drivetrain with auto-clutch and auto/sequential shifting, per-car assist levels (Casual, Sport, Sim), a spring-arm chase camera, and placeholder engine and skid audio. SI units end to end, deterministic, and it runs on primitive blockout bodies, so you need zero art to get driving.
๐ง๐ฟ๐ ๐ถ๐ ๐ถ๐ป ๐ฒ๐ฌ ๐๐ฒ๐ฐ๐ผ๐ป๐ฑ๐: install the kit, open the bundled vehiclephysics_demo scene, press play. WASD drives, mouse orbits, scroll zooms. Want to see it dressed up? Play Vehicle Prototyping, it is this kit with car models on top.
๐๐ฟ๐ถ๐ป๐ด ๐๐ผ๐๐ฟ ๐ผ๐๐ป ๐ฐ๐ฎ๐ฟ๐: define a CarDefinition (chassis, wheels, tires, drivetrain, brakes, assists), spawn it with VehicleFactory.Spawn, and plug your own models in through the CustomBodyBuilder seam. The README in Source covers the full API, the seams, and the input actions you need.
๐๐ถ๐ฟ๐๐ ๐ด๐ฒ๐ป๐ฒ๐ฟ๐ฎ๐๐ถ๐ผ๐ป, ๐๐ผ๐ฟ๐ธ ๐ถ๐ป ๐ฝ๐ฟ๐ผ๐ด๐ฟ๐ฒ๐๐. This is an early release: the core physics is proven in a shipped game, but the API surface may still move and there are rough edges. Feedback, bug reports and feature requests genuinely shape where this goes. Come tell us what you are building: https://discord.gg/JfrwFtn9T
MIT licensed. Fork it, ship it, no strings.
๐ง๐ฟ๐ ๐ถ๐ ๐ถ๐ป ๐ฒ๐ฌ ๐๐ฒ๐ฐ๐ผ๐ป๐ฑ๐: install the kit, open the bundled vehiclephysics_demo scene, press play. WASD drives, mouse orbits, scroll zooms. Want to see it dressed up? Play Vehicle Prototyping, it is this kit with car models on top.
๐๐ฟ๐ถ๐ป๐ด ๐๐ผ๐๐ฟ ๐ผ๐๐ป ๐ฐ๐ฎ๐ฟ๐: define a CarDefinition (chassis, wheels, tires, drivetrain, brakes, assists), spawn it with VehicleFactory.Spawn, and plug your own models in through the CustomBodyBuilder seam. The README in Source covers the full API, the seams, and the input actions you need.
๐๐ถ๐ฟ๐๐ ๐ด๐ฒ๐ป๐ฒ๐ฟ๐ฎ๐๐ถ๐ผ๐ป, ๐๐ผ๐ฟ๐ธ ๐ถ๐ป ๐ฝ๐ฟ๐ผ๐ด๐ฟ๐ฒ๐๐. This is an early release: the core physics is proven in a shipped game, but the API surface may still move and there are rough edges. Feedback, bug reports and feature requests genuinely shape where this goes. Come tell us what you are building: https://discord.gg/JfrwFtn9T
MIT licensed. Fork it, ship it, no strings.
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Package ID:
fieldguide.vehiclephysics
Created:
2026-07-19 15:59 UTC
Updated:
2026-07-22 03:36 UTC
Type:
library
Public:
Yes
Version:
313829
files:
91
Size:
1.2 MB
Engine Version:
28
Asset Version ID:
313829
Version Created:
2026-07-22 03:36 UTC
Hash:
1784691414
Manifest: Open manifest
Resources:
Code Package References:
Flight-Tested and Fun-Tuned
Jul 22, 2026
Added
- Opt-in per-car Sport dials on CarDefinition: SportTcSlipTarget and SportStabilityScale, so RWD cars can get their own Sport-mode traction and stability without touching Casual
- Air-attitude assist: AirPitchDampTau on VehicleController damps airborne pitch so cars land flat off jumps, and the handbrake bypasses it for deliberate flips
Improved
- Faster baseline: default PeakTorque 150 to 180 and RedlineRpm 6500 to 7800, about 20 percent more acceleration and top speed out of the box, hand-tuned per-car values are untouched
- Reverse is no longer a crawl: ReverseSpeedCap default goes 4.5 to 20 m/s, every assist audited at full reverse speed, stability damps reverse fishtails, and the gearbox still refuses to slam into forward until near-stopped
- Chassis colliders ship slick with friction 0.1, so a bottomed or landing chassis keeps its forward momentum instead of losing it to contact friction, tire grip stays the wheel model's job
Fixed
- Wheel visuals no longer sawtooth against the body on high-refresh displays, the suspension offset now rides the engine's fixed-tick interpolation exactly like the chassis
- A driven wheel that leaves the ground now freewheels instead of flaring to redline, no more engine scream over jumps, mid-air upshifts, or tall-gear landings
- Airborne wheels wind down at bearing-drag rates, they no longer arrive at half road speed after a flight and brake the car on touchdown
- The demo pad no longer mirrors ghostly white copies of the cars, it ships a matte material of its own
Known Issues
- Traction control does not act in reverse, reverse wheelspin is bounded by the drive-side rev cap instead, a proper TC pass is on the roadmap
Tune it while you drive
Jul 19, 2026
Added
- 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.
Improved
- 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.
Fixed
- 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.
Known Issues
- 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 means parked
Jul 19, 2026
Fixed
- 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.
Known Issues
- 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.
Bring your own body
Jul 19, 2026
Added
- 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.
Fixed
- 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.
Known Issues
- 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.