Chassis - Vehicle Framework for Schedule I

🛟 Need help or found a bug? Get support at support.doodesch.de/chassis.

📖 API documentation: docs.doodesch.de/mods/chassis/api/

Drivers and passengers sit in the car where you can see them, with their hands on a steering wheel that turns. Chassis adds a first person view, a horn, indicators, locks and owners, and a base interior for the vanilla cars. Other mods build their vehicles on it.

Features

• Players and NPCs in a vehicle sit visibly in their seats, police included. The driver holds the steering wheel with both hands, and the wheel turns when you steer.
• Press V in a vehicle for a first person view from your seat. Your body stays visible below you.
• Press G for the horn. H stays the headlights.
• The key hints at the bottom left show the vehicle's keys. While you push a vehicle they show Push and Let Go.
• The left and right arrow keys switch the indicators on vehicles that have indicator lamps. After the turn they switch off on their own.
• Each player-owned vehicle has an owner, and the owner can lock it. A locked vehicle lets in only its owner. Others can ride along while the owner sits inside. Other mods set the lock through the API. Vehicles from older saves belong to the host.
• The vanilla cars get a base interior: seats, a dashboard, a steering wheel and tinted glass, so you can see who sits inside.
• Every vanilla car gets a live rear-view mirror and two side mirrors. The Mirrors row in the graphics settings picks Off, Rear Only, Rear + Side (default) or + Nearby Cars, which also renders the mirrors of up to three cars within 15 m. Reflections sets how sharp they are.
• The speedometer and the rev counter move. In first person, look at a switch and left-click it: light switch, hazard lights, indicator stalk and the horn in the wheel centre.
• The vanilla cars flash their own amber indicator lamps outside. A rear without one flashes part of the brake light in red.
• Guns hit NPCs that sit in a car. A driver who goes down falls out, and the car stops.
• Riding and pushing the wheelchairs moved to its own mod, Rollin. Without Rollin the wheelchairs stay vanilla props.
• In co-op, seats, horn, indicators, locks and owners sync through the host.

Controls

Screenshots

Requirements

• Schedule I 0.4.7f12 (IL2CPP) with MelonLoader 0.7.3+.
• Every player in a co-op session needs Chassis.

Settings

BaseInterior (default true) in category Chassis of UserData/MelonPreferences.cfg. It turns the base interior and the visible NPC drivers of the vanilla cars on or off.

SpeedUnit (default kmh) sets kmh or mph for the speedometer and the odometer.

Mirrors (default 2) picks which mirrors render: 0 Off, 1 Rear Only, 2 Rear + Side, 3 + Nearby Cars. Reflections (default 1, 0 Low to 3 Ultra) sets how sharp chrome and the mirrors reflect. Both are also in the game's graphics settings.

For mod authors

Chassis has a public C# API in Chassis.Api (ChassisApi). With it you give a vehicle seat profiles, a steering wheel, lids, lamps and a horn sound, sound the horn, set indicators, and read or set owner and lock, and add your own keys to the key hints. Mods can also build their own interior with working gauges and clickable switches, and read speed, rpm, lamps and the odometer as telemetry, and keep an NPC that was shot slumped in its seat. A tuning API lets mods fit parts with their own models and driving factors, set paint, rim colour, xenon, neon, window tint, tyre smoke and horn, synced in co-op and saved with the vehicle. Profiles are JSON files in UserData/Chassis/<vehicle code>.json, and a file there wins over a profile from code. Every type and member: API reference. Source: GitHub.

License

DooDesch API License - build on the API, do not copy the code. See LICENSE.md.

This mod is written with help from generative AI tools (Anthropic Claude, OpenAI Codex).

If you have fun with it, a like on the Thunderstore page really helps other people find it (thumbs up next to Download, you need to be logged in) - ty either way, and lemme know if anything breaks or you've got ideas

Changelog

All notable changes to Chassis are documented in this file. The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[1.12.1] - 2026-11-10

Fixed

• An officer who wants to search you in a car no longer starts a chase at once. He pulls you over, walks to your window and searches you in your seat. Driving off still counts as failure to comply.

[1.12.0] - 2026-11-10

Added

• Getting into a car starts in the view you had when you last got out. StartInFirstPerson starts every seat in first person.

Fixed

• After honking at a police checkpoint, the view no longer jumps to where you got into the car once the officer has talked.
• The checkpoint officer no longer walks back and forth when the spot beside the driver door is blocked.

[1.11.0] - 2026-11-09

Added

• Use hotbar items in any vehicle seat: eat, drink, smoke and hold weapons. Weapons fire in first person, and trash goes out of the window.
• Optional ignition: turn the key beside the wheel (I) to switch the engine off and on, or press the auto ignition button to drive as before.
• The tag on the ignition key has the colour of the car and changes with it when the car is repainted.
• Honk at a police checkpoint to call the officer to your window. He searches the car while you stay inside.
• Indicator, first person and ignition keys can be changed, and each can get a controller button ([Chassis] in MelonPreferences.cfg).

Fixed

• Underglow lights the ground as one even strip instead of separate spots.
• The driver no longer shows standing for a moment when getting into a car.

[1.10.4] - 2026-11-07

Fixed

• Suspension upgrades lower the car again. Every stage raised the body instead, on every car, most visible on the Cheetah.

[1.10.3] - 2026-11-05

Fixed

• Cabin light and rear-view mirror no longer poke through the windscreen. Most visible on the Cheetah, the mirror corner also showed on every car except the Hotbox.

[1.10.2] - 2026-11-05

Fixed

• Side mirror glass follows the rounded shape of the mirror on the Cheetah, Hounddog, Veeper and Hotbox, instead of a rectangle with its corners sticking out.

[1.10.1] - 2026-11-05

Fixed

• Side mirrors of the Cheetah and the Hounddog show the whole mirror instead of a grey face with a thin strip. Reported by MR.Monkey.
• The Veeper's side mirror glass fills its whole mirror.

[1.10.0] - 2026-11-05

Added

• Cabin light in the vanilla cars: it fades on when someone gets in or out and while the car stands, and off when you drive.
  • Click the dome lamp to switch between Auto, On and Off.
• Glovebox right of the centre console, reachable from both front seats, also while driving. 2 to 4 slots by car size, saved with the car.
  • GloveboxOwnStorage = false makes the lid open the trunk instead, so saves stay vanilla.

[1.9.2] - 2026-11-03

Fixed

• With MirrorShowsOwnCar on, the side mirrors no longer show the edge of their own housing in the middle of the picture.

[1.9.1] - 2026-11-03

Fixed

• The left and right arrow keys switch the indicators in vanilla cars again, and the key hints bottom left list them.

[1.9.0] - 2026-11-03

Added

• Every vanilla car has a live rear-view mirror and two side mirrors.
• A Mirrors row in the graphics settings, below Reflections: Off, Rear Only, Rear + Side (default) or + Nearby Cars.
  • • Nearby Cars also shows the mirrors of up to three cars within 15 m, on foot too. Setting: Mirrors.

Changed

• Reflections also sets how sharp the mirrors are.

Fixed

• Chrome paint now reflects the sky and looks brighter.

[1.8.3] - 2026-11-02

Fixed

• Cars keep their windows and interior at a distance, and a hidden car no longer leaves its interior floating.
• NPCs put their umbrella away while driving.

Changed

• Thunderstore and Nexus Mods may now review the mod files: the license names their package review as an exception.

[1.8.2] - 2026-11-01

Fixed

• Less stutter with several chrome cars on Reflections Ultra: they share one refresh rate, and near cars refresh more often than far ones.
• The speed display no longer stays on screen for co-op clients after they leave a vehicle.
• Loading a save several times without restarting the game piles up far less memory for car interiors.

[1.8.1] - 2026-10-28

Fixed

• The horn no longer carries across the map: it fades with distance, sounds duller far away and is silent past 80 m.

[1.8.0] - 2026-10-27

Added

• New "Reflections" row in the graphics settings, Low to Ultra. High and Ultra give sharper chrome that updates faster.

Fixed

• Tuned cars no longer reverse almost as fast as they drive forward.
• Lowered suspension now shows on big vehicles like the RV.
• Underglow no longer lights the inside of the car.

For mod authors

• ChassisApi.HornClip returns the sound a vehicle's horn plays.

[1.7.1] - 2026-10-27

Fixed

• Window tints are clearly darker; the game's fog washed them out to grey.
• Changing the window tint no longer flashes the stock body colour for a moment.
• Chrome paint looks like chrome and reflects the street around the car, also while it drives; metallic paints look metallic.
• Neon lights the ground in an even band along the sills and bumpers, with no tube in sight.

[1.7.0] - 2026-10-26

Fixed

• Key hints on Left Ctrl show up at the bottom left: the game has no picture for that key and dropped them.

For mod authors

• ChassisApi.PreviewTuning, PreviewPart and EndPreview show a part or a paint on this machine only, without saving or syncing it.
• ChassisApi.SetPaintTargets puts the body paint on your own model instead of the stock body; Secondary targets take the second paint.
• ChassisApi.PaintRenderers paints a model with no car under it, on this machine only.
• ChassisApi.AddKeyHint takes any key: one the hint strip has no picture for is drawn on a wide key with its name.

[1.6.1] - 2026-10-22

Fixed

• The cheetah's body beside the rear window is no longer see-through.

[1.6.0] - 2026-10-22

Fixed

• Cars bought while Steam was not ready at the start are yours again in a lobby: locked cars let you in and the Yesla app shows.

For mod authors

• SeatProfile.Recline leans the seated body back about the hips with a straight back; hands, feet and eyes keep their points. Console: chassis profile set recline <degrees>.

[1.5.0] - 2026-10-22

Added

• Drivers hold the steering wheel: both hands close around the rim and turn with it, for you and for NPC drivers.

For mod authors

• HandProfile.RimRadius, RimThickness, RimOffset and GripAngle close the hands around the rim. FitSeat measures RimRadius from the wheel's mesh.

[1.4.0] - 2026-10-21

Added

• Hold G to keep the horn sounding; it stops when you let go.
• Steering is calmer at speed: the wheels turn less the faster you go and ease back to straight. SpeedSteering turns it off.

[1.3.0] - 2026-10-21

Changed

• The drivable wheelchair moved into its own mod, Rollin. Install Rollin to keep riding and pushing wheelchairs.
• A repaint at Marco's replaces paint that a tuning mod gave the car.

For mod authors

• Tuning API: RegisterTuningPart, InstallPart and RemovePart for parts with their own model and driving factors.
• Built-in parts: engine, brakes and transmission stages 1-3, suspension 1-4, turbo, drift tyres.
• SetPaint (primary, secondary, finish), SetRimColor, SetXenon, SetNeon, SetWindowTint, SetTyreSmoke and SetHorn. SetTuning and GetTuning store keys of your own mod.
• The host checks each change against the owner, syncs it and saves it with the car. TuningStatsOf and TuningChanged read it.
• PoseAsPusher, ReleasePusher and PushedBy let a player push a vehicle from behind, as Rollin's wheelchair does.

[1.2.0] - 2026-10-21

Added

• The speedometer and rev counter in the vanilla cars move, dash lamps show indicators and headlights. SpeedUnit sets kmh or mph.
• In first person, look at a dash switch and left-click it: lights, hazard lights, indicator stalk (also mouse wheel), horn. Switches click, indicators tick.
• A dot in the screen centre shows where you look while your view is below the windscreen, with the switch's name.
• The vanilla cars flash their own amber indicator lamps outside, at the rear part of the brake light in red where a car has none.
• Guns hit NPCs in cars. A driver who goes down falls out and the car stops.

Fixed

• Vehicle owners and locks are no longer lost when the game saves.
• Seats and the driver's legs no longer stick out under the cars.
• The steering wheel no longer spins faster than the hands could turn it.
• Getting in crouched no longer leaves you crouched in the seat.

For mod authors

• ChassisApi.SetInterior builds your own interior; ChassisProfile.Gauges and ChassisProfile.Controls bind needles, lamps, digits and clickable switches.
• ChassisApi.Telemetry, ReadGauge and RegisterGaugeSource: speed, rpm, pedals, lamps, steering, clock, odometer, trip, each with a validity flag.
• RegisterControlAction, UseControl, ControlUsed and the events HeadlightsChanged, BrakeChanged, ReverseChanged, DriverChanged.
• RegisterOccupantDown keeps a shot NPC slumped in its seat instead of falling out; RemoveOccupantDown removes it.
• chassis telemetry and chassis zones work in the release build. The GitHub release also carries Chassis_1.2.0_debug.zip with the developer console commands.

[1.1.0] - 2026-10-20

Added

• The key hints at the bottom left show the vehicle's keys: V First Person, G Horn, and the arrow keys for Indicators on vehicles with indicator lamps.
• Behind a wheelchair the key hints show Push and Let Go, with your own key bindings.

Fixed

• NPCs in low cars like Sam's and Michael's Coupe drive off again instead of sitting still at the curb.

For mod authors

• ChassisApi.AddKeyHint puts your own key into the key hints, a fixed key or one from your preferences. RemoveKeyHint takes it out.
• The show callback gets a KeyHintContext with Vehicle, Profile, Seat, Driver and Pushing.

[1.0.1] - 2026-10-20

Changed

• Chassis has its own icon in Thunderstore and r2modman.

For mod authors

• Every type and member is listed in the API reference, linked from the README.

[1.0.0] - 2026-10-20

Added

• You sit visibly in the driver's seat with both hands on the wheel, and the wheel turns as you steer. Co-op players see it too.
• Press V in a vehicle to switch to first person.
• G sounds the horn. The left and right arrow keys set the indicators on vehicles that have indicator lamps.
• Vanilla cars get seats, a dashboard, a steering wheel and tinted glass. NPC drivers sit visibly, police included. BaseInterior turns both off.

For mod authors

• ChassisApi.Register adds a vehicle profile from code; FitSeat builds a seat profile from the vanilla seat.
• Honk, SetIndicator, SetLocked, SetOwner, SetPart and SetStorageEnd act on a LandVehicle and sync in co-op.
• FirstPersonActive, FirstPersonChanged, IndicatorChanged and OwnersChanged report state to your mod.