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.
• 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.

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

MIT. See the included 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.

[1.6.1] - 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.