Simple Offroad Physics Controller - 4x4 Vehicle, Axle Suspension, Crawler

Stop fighting Wheel Colliders. Get real solid-axle articulation.

Simple Offroad Controller replaces Unity's WheelCollider with a raycast-based solid-axle system that gives you independent left/right wheel travel per axle, true differential locking, and a full tunable drivetrain, from the engine torque curve and gear ratios to spring rates, damper curves, and differential bias ratios.

Use the Auto-Configure wizard to go from meshes to a driving vehicle in under a minute, or build your hierarchy manually for full control.

Solid-Axle Physics

• Real articulation with independent left/right suspension travel per axle
• 4-ray wheel cast: center, left edge, right edge + forward-down step detection at 30°
• No WheelCollider, every ground interaction is custom raycast
• Spring-damper suspension with adjustable ride height, bump travel, droop, spring rate, and damping
• Anti-roll bar per axle with tunable stiffness

Drivetrain

• Engine simulation: multi-keyframe torque curve, rotational inertia, kinematic RPM coupling (engine speed driven by wheel speed through gear ratios), stall detection
• Automatic transmission: configurable gear ratios (4/5/6-speed presets), shift-up/down RPM thresholds, shift duration
• Differential models: Open, Locked, and Limited-Slip with configurable torque bias ratio
• Low range (4LO): torque-multiplying transfer case gear
• Toggleable 4WD: switch between 2WD and 4WD per axle on the fly

Tire Model

• Three-region lateral force curve (linear climb → gradual falloff → residual grip)
• Peak slip angle, max slip angle, and slide grip ratio, fully tunable per axle
• Friction circle coupling — throttle and brake forces interact with lateral grip
• Relaxation length, lateral force builds based on tire rolling distance, not a fixed timer, for realistic weight feel
• Speed-scaled force response (progressive turn-in at low speed, responsive at high speed)

Steering

• Max steer angle, sensitivity, smooth speed, and auto-return per axle
• High-speed reduction, reduces effective steering angle at speed for a forgiving arcade feel
• Reference speed control for reduction curve
• Invert steer per axle

Presets (One-Click Setup)

• Vehicle presets: Rock Crawler, Trail Rig, Overlander, Baja Racer — set weight, engine, transmission, suspension, differentials, and aerodynamics in one click
• Engine presets: V8 (diesel torque), V6 (balanced), I4 (high-RPM), I6 (broad flat curve)
• Transmission presets: 4, 5, or 6-speed gearboxes

Input

• New Input System (PlayerInput / .inputactions asset) via OffroadInputSystem — auto-added, no manual wiring
• OffroadInputDelegate for code-driven control: AI, testing, networked vehicles
• Max throttle slider for keyboard demos
• Auto reverse hold brake at standstill

AI Driver (BETA)

• Pure pursuit steering on a smooth Catmull-Rom spline path
• Curvature-based speed planning with approach braking and recovery zones
• Speed-adaptive lookahead distance
• Obstacle avoidance (optional, 5-ray fan)
• 4WD, low range, and e-brake support
• Auto-rebuilds path when waypoints move in the editor

Camera

• Forza-style follow camera with velocity look-ahead
• Mouse freelook with auto-recenter when driving
• Speed-based pushback and ground-height avoidance
• Multi-camera manager for switching (interior, chase, bumper, etc.)

Effects & Feedback

• Tire noise, velocity-based lateral slip with configurable volume/pitch curves and cooldown
• Dust particles on slip
• OffroadAudio, dual AudioSource with RPM-blended pitch/volume crossfade (idle + running), shift sounds, stall muting
• OffroadLightManager, 4-state cycle (Off → Main → HighBeam → Accessories) with automatic brake and reverse lights
• OffroadInfo (telemetry), real-time HUD overlay showing RPM, gear, speed, torque, compression, articulation, differential mode, and more
• Rich gizmo visualization, axle center, suspension travel, bump/droop stops, steer cone, spring zigzag

Vehicle Features

• Traction control (strength 0–1)
• Brake torque and e-brake per axle
• Parking hold with configurable speed threshold and hold force
• Aerodynamics, drag and downforce with speed-squared scaling
• Manual transmission mode support

What's Included

• 17 C# scripts (runtime + editor)
• Custom inspectors with preset buttons, sliders, and real-time gauges
• Auto-Configure editor wizard (body + wheel setup)
• Full documentation with setup guide, component reference, and tuning tips
• Demo scene with a fully configured vehicle