Vehicle & Engine Simulator

About the content

This manual covers every part of Vehicle & Engine Simulator, a Blender add-on that turns a car, motorcycle or truck model into a vehicle you can drive in the viewport, with vehicle physics underneath and an engine sound built from the simulation's own rpm. There is one chapter for each area of the Vehicle Sim tab.

It needs Blender 4.2 or newer, and the wheels of your model must be separate objects from the body. Cars, motorcycles, and trucks on three axles or more all work.

Warnings and symbols

Different types of notices and symbols are used in the descriptions.

Instructions and text

• Bold names are buttons, settings and panels exactly as they appear in Blender.
• Italic paths such as Preferences → Add-ons tell you where to click.
• Keys are the default key bindings.
• Panels drawn from the add-on respond like Blender's, shown with an Audi RS7 loaded: drag or click a number, tick a box, open a menu or fold a panel.

An instruction that you carry out.

1. Steps that you carry out in this order.

Fig. 1 numbers the pictures in each chapter.

Getting started

The add-on installs as a Blender extension. Everything it does is in the Vehicle Sim tab of the 3D view sidebar (press N).

The tab opens on a card for the car — its name, drivetrain and gearbox, power, torque and weight — with the Drive bar under it: Drive (Live), Drive + Record and Reset. Below that is a row of tabs: Rig, Vehicle, Chassis, Driver Aids, Sound, Lights, FX, Camera & Recording, and Everything, which stacks all of them in one list. Garage, Settings and Race open as pages from the bottom of the tab. The tabs name themselves once the sidebar is wide enough for the words.

Press Alt + V in the viewport, or right-click → Vehicle Sim, for a quick menu: drive and record, the driver aids, the suspension mode, gearbox, camera, HUD and time scale. It opens mid-drive too.

Settings that apply to every file — key bindings, the controller, the acceleration timer, the engine curve's look and the experimental switch — are in Preferences → Add-ons → Vehicle & Engine Simulator. The Settings page of the tab shows the controller and the key bindings too.

Build a rig

1. Open or import your car. Any model works, as long as the wheels are separate objects from the body. For a motorcycle, set Parts → Vehicle to Motorcycle; for a truck, press Add Axle under Parts for each axle past the front and rear pair.
2. Find Parts. Finds the wheels and body and reports the wheelbase, track and tire radii. Assign anything it missed in the Parts list. Four wheels named by their corner (Front Left …) make a car even when two loose tyre objects sit inside them in a line. Three wheels, one at one end and two at the other, make a three-wheeler: Build Rig says so first and puts the lone wheel on the centre line.
3. Build Rig. Creates the hubs, steering, suspension, collision shapes and sound emitters. Everything is named CARSIM_* and kept in its own collection. With Bring Loose Parts on (under Body in the Parts box, on by default) it also attaches whatever sits inside the car that no slot names — lamps, glass, an interior, brake discs, a spare tyre object — so nothing is left standing when the car drives off. A round part on a wheel's axle (a disc, a rim) spins with the wheel; anything else inside a wheel (a caliper, a ball joint) turns with it without spinning; the rest rides on the body. Before you build, the Loose Parts fold under the Parts box lists what will come along and where each goes; the arrow selects one to see which it is, and X leaves it out (it stays where it is; + takes it back in). After the build it lists what came, and Remove Rig puts each one back.
4. Drive (Live). The viewport becomes the car. Press Esc or Enter to stop.

Proxy Detail sets how closely the body collision shape follows the bodywork (see Ground & collisions). The sound emitters are created selected — move them to the engine bay and the tailpipe.

After the build

Check that the hubs sit at the wheel centres. A car that pulls to one side on a straight almost always has a hub slightly out of place — click the wheel on the map in Rig → Parts and set its Hub Depth (Hub Centre is there too). The wheel colliders are under Rig → Colliders: like the hubs, they are built into the rig, so they sit beside it.

The Rig tab

Under Remove Rig, four buttons pick what the Rig tab shows, one at a time: Parts, Suspension, Colliders and View. On a narrow sidebar the buttons show their icons alone. Which one is open, and what is picked in each, is kept with the scene and saved in the file; a new scene opens on Parts.

• Parts is the vehicle seen from above: FRONT, the front wheels (each with its wheel and caliper), the body in the middle, the rear wheels, REAR. The body is one object or a collection of its pieces, or both: either one sets it. A motorcycle has its Fork beside the front wheel, its Swingarm beside the rear, and the Drive Chain under it; a car has the Drive Chain too, and Add Axle for a truck's extra axles, each a pair of wheels with its end, whether it is driven, and ✕ to remove it. Click a part's name and its other settings show in the box under the map: a wheel's spin centre and hub depth (with Hub Centre and Calipers Spin With Wheel, which are for every wheel), more collections on the body and the loose parts Build Rig brought along, the fork's and the swingarm's collections, the chain and its sprockets. Loose Wires is a list under the map: + adds one, − removes the picked one, and its ends are in the box. On Blender's own sidebar width the map's cells sit one under the other; widen the sidebar and a pair sits side by side, as on the car.
• Suspension is Built-in or From Model, and the list of the suspension's units (see Suspension units).
• Colliders and View are lists — Ground, Wheel Colliders, Body Proxy, Walls, Cars & Rollover; Overlays, Move By Hand, Centre of Gravity — each row saying what is set in it (Flat Plane, cylinder ×32, 4258 faces). Pick a row for its settings.

Remove a rig

• Keep My Settings — deletes only the rig objects. Sound emitters, smoke setup, tire-mark material and all panel settings stay, ready for the next rig. The dialog opens on this one.
• Clear Everything — removes all of it, and puts every setting back to its default.

If you would rather it opened on Clear Everything, turn on Remove Rig Opens On Clear Everything in the add-on's preferences. With Confirm Before Deleting off there is no dialog, and Remove Rig does whichever of the two it would have opened on.

Controls

Defaults are shown below. All keys can be changed in Preferences → Add-ons → Vehicle & Engine Simulator → Keyboard Controls.

Controller

A PS5 DualSense works over USB or Bluetooth, and an Xbox controller — or any pad in Xbox mode — through XInput on Windows, wired or wireless. Either is picked up automatically; Controller in the preferences can hold it to one kind. The button map is in Controller Controls (PS5 DualSense) in the add-on preferences, and an Xbox pad uses the same buttons by position (A for Cross, B for Circle, LB for L1). Hold L1 + R1 for a second to start or stop the engine.

Every button on the DualSense can be assigned: besides the face buttons, the bumpers and the d-pad, L3 and R3 (the stick clicks), Create, Options, the PS button, a touchpad click and Mute. They do nothing out of the box. Every action the keyboard has can go on one of them — reset, the automatic gearbox, HUD and cluster style, lights, cruise control, the race start, and starting the engine with a single button. Only the triggers are fixed, as the gas and the brake. On an Xbox pad View and Menu are Create and Options and the stick clicks are L3 and R3; XInput does not report the Xbox button, so PS, touchpad and Mute have no Xbox equivalent. Mute is not sent over Bluetooth until the pad switches to its full report.

The pad talks back. Rumble feels wheelspin, the rev limiter, kerbs, gearchanges and crashes. On a DualSense, adaptive triggers make L2 push back like a brake pedal and pulse under ABS, and R2 buzz when the driven tires spin, and the lightbar is a shift light — or a power meter on an electric car. Each has its own switch.

The car

Every panel in this chapter is per car. With several cars in a scene, the panels show whichever car is active in the Garage.

Presets

136 vehicles ship with the add-on: 125 cars — 68 rear-drive, 54 all-wheel drive and 3 front-drive, seven of them electric — plus 6 motorcycles, 3 trucks and 2 trailers. A preset sets engine, gearing, weight, aero, suspension and tires together. The magnifier beside the preset list searches every preset by brand or name. Match Tone To Vehicle then points the engine sound at the same figures.

Powertrain

Powertrain, at the top of Vehicle, is Combustion or Electric, and each shows only its own settings. An electric car has a Motor (power, torque, max rpm), a Battery with its charge and range, and Regeneration: One-Pedal sets how hard a lift slows the car, with Hold At Stop or Creep below it, and the brake pedal blends the motor and the friction brakes so it brakes the same either way. It runs a single-speed or a 2-speed gearbox, and starts at the flick of a switch: READY, no crank.

Engine curve

Engine Curve, in the Vehicle tab, draws torque and power against rpm from the same numbers the physics drives on, with the redline shaded and the peaks underneath. The button beside it opens it larger in a window of its own. Pick its look — Standard, Dyno Sheet, Comic or Graph Editor — under Engine Curve style in the add-on preferences.

Mass and balance

Mass, Front Weight, CG Height and Unsprung Mass decide most of how the car behaves. Rear Unsprung Mass gives the rear axles a figure of their own, for a truck whose drive axles weigh about twice its steer axle; 0 uses the front's.

Turn on Centre of Gravity (Rig tab, View) to see where the CG is: a marker centred across the car, Front Weight of the way from the rear axle to the front and CG Height above the road, with the sprung body's own CG beside it (smaller, blue) and a dot at each hub for the unsprung mass. Drag the ring on the marker to move it — easiest from the side (Numpad 3): along the car sets Front Weight, up and down sets CG Height, and the readout in the panel follows (as the marker follows Front Weight and CG Height on the Vehicle tab, where they are set). One drag is one undo step; Esc or right-click puts it back. The marker turns red, and the panel says why, when the CG is below the axles, higher than the track is wide (it would tip before it slid), or when the axles weigh more than the split leaves the body. While you drive, and in a played-back take, the marker rides with the body and a pink dot on the road shows the centre of the tyre loads against a ring where it sits at rest: it moves forward under the brakes and out in a corner. A motorcycle's marker also moves with the rider hanging off. It is never rendered.

Fuel is a section of its own in the Vehicle tab, between Shifting and Cylinder on Demand. Fuel Load is off by default. Give it a load to model the tank: Tank Size, Tank Position, and Burn Fuel, which empties the tank as you drive and shifts the balance.

Engine and aero

Peak power and torque with their rpm, redline, idle and Engine Inertia (how fast the engine revs up). Speed Limiter caps top speed. Drag CdA and front/rear Downforce (at 30 m/s) set the aero.

Engine management

Induction

Naturally aspirated, turbocharged or supercharged. Peak Boost and Spool set boost and lag.

Estimate Engine

Works out capacity, cylinders, VE and injector size from your power and torque figures. The quickest way to a car that runs.

Fuelling and Map

Closed-loop fuelling with trim authority, injector flow and dead time. Generate Base Map fills the VE and air/fuel tables; Show Table displays them.

Shifting

Automatic modes (Normal, Sport, Eco), shift points, shift time and torque cut. The line above the sliders shows the actual rpm each shift point works out to.

Drivetrain

Layout (front, rear or all-wheel drive with a front split), limited-slip diff, gearbox and final drive. Automatics add a torque converter, idle creep and a parking pawl. The rolling radius shown at the bottom comes from the rig.

On a hill, off the brake and the throttle, a manual, a dual-clutch or a motorcycle rolls back as a real one does with its clutch in; an automatic creeps and holds on its converter. A clutch start lets the clutch out as far as the hill needs.

Motorcycles and trucks

A motorcycle is steered by asking for a lean: the rider finds the bar angle that gets there, counter-steer included, and it corners on its camber. Max Lean caps the lean. Below Feet Down Below the rider puts a foot down and the bars steer it directly. Steering Parts takes the fork, bars and headlight, which turn with the front wheel about the steering head at its Rake. Wheelie and stoppie control and a lean-aware traction control are in Driver Aids, under Riding. In a hard stop the rider takes the engine's drag off the rear wheel, as a clutch hand or a modern bike's engine brake control does, so engine braking cannot lock it. Each bike brings its own Launch RPM. A bike that falls is picked back up by Rollover Recovery.

The steering is a part of the bike in its own right: the front end turns about the steering head under the tire's force at the Trail, the load as the bike leans, the front wheel's spin and the Steering Damper, and the rider's hands steer it with the torque they put on the bars. Ridden, the bars go where the rider aims and a steady turn takes only a few N m. A damper steadies the front end's shake (wobble, about 8 Hz) but takes damping away from the whole bike's slow snaking (weave, 2–4 Hz at speed). Steering Inertia is the front end's: a fairing on the fork makes it far bigger. The rake closes and the trail shrinks as the fork dives.

The rider moves on the seat: Hang Off is how far they slide across into a corner at full lean, which moves the weight in so the bike leans less for the same corner, and they slide forward when braking and over the tank when the front lifts.

The rear wheel swings on its swingarm, from the rig's Swingarm Parts and the gearbox sprocket in Drive Chain when there are any. Final Drive (chain or belt) and the Front and Rear Sprocket teeth set the line the drive pulls along, which is the bike's anti-squat; Anti-Squat scales it (1 is the geometry as it is). A shut throttle holds the wheel back through the chain's bottom run and the rear brake through the swingarm's pivot, so the two settle the rear differently. Rear Progression is the rear linkage's rising rate, and the rear damper rises with it; Fork Progression is the fork's air gap. Each built-in bike has its own rear wheel travel under Separate Rear: a cruiser's rear has far less than its fork.

The sprockets in Drive Chain (in the rig's parts) move with the bike once the rig is built. The Rear Sprocket is bolted to the wheel: it turns with it and rides the swingarm's arc with the hub (left alone if it is already a child of the wheel). The Front Sprocket turns on the frame, about its own centre, at the wheel's turn times rear teeth / front teeth from the Front and Rear Sprocket settings: the chain's speed. Both follow a ride, a played-back take and a scrubbed timeline, and Remove Rig puts each back where it hung. Build Rig counts the teeth on your modelled sprockets; when they differ from the settings the Drive Chain box says so, and Use sets the settings to your model's (these teeth are also the chain line the physics reads, so the anti-squat moves with them). The front sprocket's centre is in the Hardpoints list, to move the point it turns about.

A car or truck can have a Drive Chain too: a kart, a cyclecar, a chain-drive lorry. Fill the same slots, and pick the rear wheel it drives under Chain Drives (Rear Left or Rear Right); Front Teeth and Rear Teeth sit beside it. Build Rig strings the chain from the gearbox sprocket to that wheel's sprocket: the rear sprocket turns and rides up and down with the wheel, the front one turns on the frame at the teeth's ratio, and the links run round as the wheel turns. On a car the chain is drawn only: the car's gearing is its Final Drive, and a car has no chain line in its physics.

More Chains, under the Drive Chain box, adds as many more as you need — a twin-chain cyclecar, a chain to each rear wheel of a lorry, a bike's primary chain. Each has its own Chain, Front Sprocket, Rear Sprocket, Link Spacing, the wheel it Drives and its own Teeth, and is strung, turned and put back exactly as the first. They are drawn only: the physics reads the first chain's teeth. Build the rig again (or Rebuild) after adding one.

A truck's extra axles go in the Steered group (a twin steer) or the Rear group (a tandem or a tag axle), and take that end's springs, bars and alignment. Turn Driven off for a tag axle. A rear bogie shares its load between its axles, and a truck stands on truck tires.

A truck's ladder frame twists between its axle groups: Frame Stiffness, in Suspension & Steering, is how much (N m per degree; 0 is a rigid body, as every car is). Each end then rolls on its own springs, and a wheel climbing a rock twists the frame instead of lifting the far corner off the road. The built-in trucks' frames are softer than their axles, as real truck frames are.

The cab rides on mounts of its own on the front of the frame: Cab Mass (0 for none), Cab Ride (its bounce frequency on the mounts) and Cab Damping. It nods forward when you brake and leans out in a turn, and soaks up the frame's shake; soft mounts ride smoother over small bumps but pitch more. Put the cab shell, doors, mirrors and interior in a collection and pick it as Cab Parts in the rig's parts (under Body, with the other cab settings), then rebuild the rig: those parts ride with the cab, and so does the interior camera. On a small or narrow rig a heavy cab can outweigh the end of the frame it sits on; it then moves just the same but pushes back on the frame as a lighter cab would, so it can never throw the truck.

The built-in 6x4 hangs its steer axle on leaf springs and its rear bogie on air, the common tractor layout; the 8x4 tipper is on leaves all round, with a helper leaf at the rear. A leaf bogie passes each axle's brake and drive torque through its springs, so braking lightens the leading axle and driving lightens the trailing one; an air bogie's arms carry it themselves.

Suspension & steering

Architecture

Choose front and rear separately from six layouts — MacPherson strut, double wishbone, five-link, semi-trailing arm, twist beam and live axle — on coil, air, hydropneumatic or leaf springs. Rear Springs puts the rear on springs of its own (As Front keeps the front's): leaf at the front and air at the rear is how most trucks are hung. Air springs add a pressure and levelling rate; a front and rear payload loads the car up. Air and hydropneumatic springs level each axle group on its own, so a load in the boot brings the rear back up without lifting the nose, and a group on steel is not levelled at all.

Leaf springs rub, which is most of a truck axle's damping and makes small bumps meet a stiffer spring. A leaf rear can carry a Helper Leaf: a second pack the main leaves only reach once the load on each spring passes Helper Load, so an empty truck rides on the main leaves alone and a laden one on both.

A twist beam cambers part way between its trailing arms and a live axle in roll, the cross member sitting between the arms' pivots and the wheels.

Your own suspension parts (From Model)

By default the add-on draws a suspension of its own — a wire-frame linkage laid out from the settings above — and your modelled arms, shocks and tie rods ride rigidly with the body or the wheel. Suspension Rig, in the Rig tab, switches that: Built-in is the add-on's linkage, exactly as before; From Model rigs your parts, so the arms swing on their bushes, the knuckle follows its ball joints and tie rod, the shock telescopes between its eyes and the spring compresses between its seats. It is drawing only: the car drives the same either way.

1. Model the parts as separate objects, one per part: each arm, the knuckle, the shock body and the shock shaft (two objects, so it can telescope), the spring, the tie rod, and on a motorcycle the rocker and the dog-bone. A part made of several pieces works best joined into one (Ctrl+J). Put them in a collection of their own.
2. Build the rig as usual, then open Rig → Suspension and pick From Model. The section reads as four numbered steps, each ticked once it is done: 1 your parts' collection, 2 the slots (a fold, open at first, with Assign by Name on its header: the units drawn as the vehicle seen from above, with the picked one's slots under it), 3 Find Hardpoints and what it found, 4 adjust the picked unit's markers and Rebuild. A file from before a slot was added shows the slots it has and an Add Missing Slots button for the rest. Only the slots most models need are shown at first (for a car corner: the arms, the knuckle, the shock, the spring and the tie rod); the rest — ball joints, extra links, the anti-roll bar, mounts — show once filled, or with Show Optional Slots. Hover a slot's name, or its box while it is empty, to see what part goes in it; clicking the name puts the same words in the status bar. The + beside a slot adds another box under it for a second part of the same kind — a second spring, a bush, a shaft in two pieces: it moves exactly as the slot's own part does and is never read for hardpoints; − takes it away and puts the part back.
3. Suspension Parts: pick the collection, and press Assign by Name. It fills the slots from the parts' names (Lower_Arm, UCA, Knuckle, Shock_Body, Shock_Shaft, Spring, Tie_Rod, Sway_Bar, Panhard, Rocker, Dog_Bone and the like, in several languages) and from where each one sits for its corner. Check each unit's slots (pick it on the map) and pick or clear any it got wrong; slots you filled yourself are never overwritten.
4. Find Hardpoints. Reads every pivot, ball-joint centre, shock eye, spring seat and tie-rod end off the meshes, marks each with a small sphere, solves the linkage and rigs your parts on it. The box under the buttons says what it found, or why it could not. The linkage is solved about the wheel's own centre, in the middle of the tyre, wherever Hub Depth has put the hub. Whether the Upper Arm / Strut slot holds a strut or a control arm is read from its shape (a strut stands up from the knuckle, an arm lies across the car); if that is not what Front or Rear Linkage says, the setting is changed to match and the status bar says so. A shock's or bar link's end goes on the part whose surface it is nearest.
5. Check the markers. A bush, ball-joint housing, shock eye or rod-end ball that is a separate piece of the part's mesh is read at its own centre, exactly. A rod or link in one piece is read a radius back from its round end. A wishbone's ball joint or bush that is neither is read at the end of the part, and the box lists it: drag those markers onto the joint (and any others that are not where the pivot really is), then press Rebuild (Rebuild keeps your markers; Find Hardpoints reads them all afresh).
6. Drive. Your parts move with the suspension while you drive, when a take is played back, and when you scrub the timeline.

Car corner slots

Lower Arm and Upper Arm (a wishbone's two bushes or a single link's one are told apart by shape), Upright / Knuckle, Lower and Upper Ball Joint (optional: without them the arms' outer ends are used), Shock Body, Shock Shaft, Spring, Tie Rod / Toe Link, Anti-Roll Bar Link three Extra Links / Radius Rods for a multi-link, and the parts that ride the linkage without locating the wheel: the Strut Top Mount and Bump Stop / Helper (on the half of the shock fixed to the body — the shaft on a strut), the Steering Arm (on the knuckle) and the Drive Shaft / Half-Shaft (hung off the hub, aimed at the diff: its inner joint plunges as a real one does, and it turns with its wheel as you drive). A shaft modelled in two pieces goes in one slot and an added one (+ on the slot): a piece between the joints moves with the shaft, and a piece inboard of the inner joint — an intermediate shaft on its bearing, the diff’s output — stays on the body and spins about its own line. The Drive Shaft Boot slots take each joint’s rubber boot: its big end stays on the joint’s housing, its small end on the shaft, and it bends between them as the wheel moves and steers. Keep each boot as its own object, apart from the shaft. Assign by Name also takes a half shaft named as one from anywhere in the scene, since they are often kept with the driveline rather than the suspension. When the Upper Arm / Strut slot holds a strut, it rides the knuckle, and the top mount is the end at the top. On a trailing-arm axle the lower arm is the trailing arm.

Axle slots

Anti-Roll Bar on every axle, with the Steering Rack Bar (it slides with the steering) and the Sub-Frame / Crossmember on an axle of arms. A live axle (and each truck axle) has Axle Housing, Panhard Rod, four Axle Links / Torque Rods and a Watt's Link (its centre and two rods: the centre turns on the axle so the rods keep their lengths) instead of arms; its shocks and springs are per wheel, and each wheel also has a Leaf Spring (its eyes stay on their hangers and its middle rides the axle, bending between), Leaf Shackle (drawn on the frame with the leaf's eyes), U-Bolts / Spring Plate (on the axle) and Bump Stop. The axle slides sideways as it rises so its Panhard rod keeps its length. A Watt's link is drawn only: the roll centre still comes from the Panhard rod or the settings.

Drivetrain slots

The Drivetrain row sits on the map between the front axle and the rear wheels. Its shafts stay where they are on the body and turn about their own length as you drive: the Front and Rear Prop Shaft at the pinion's speed (that end's wheels times the Final Drive), the Centre Shaft with the driven pinions, and the Front and Rear Diff Cross Shaft (the shaft through a diff, between its two half shafts, as one part) with that end's wheels. An end the engine does not drive stands still, so on a rear-wheel-drive car the front ones do not turn. A prop shaft turns about the middle of its tube, not a flange or yoke at an end; a cross shaft about the line through its two ends. Assign by Name puts a part called a prop, propeller, centre or tail shaft in the prop shaft slot for the end it sits at (the middle third of the car is the Centre Shaft), and a drive shaft that runs across the middle of the car through a diff in that diff's cross shaft slot. A shaft modelled inside the diff's object has to be split out into an object of its own to turn.

Motorcycle slots

Shock Body, Shock Shaft, Spring, Rocker and Dog-Bone / Pull Rod (and a second dog-bone plate), the Shock Reservoir (on the shock body), Rear Caliper / Hanger (on the axle, not turning), Chain Guide / Slider (on the swingarm) and the Brake Torque Arm (from the hanger to the arm, swinging between). The fork already has Fork Top and Fork Bottom, and the swingarm its Swingarm Parts. Rocker Pivots On says whether the rocker turns on the frame or on the swingarm; Auto works it out. Without a rocker the shock runs straight from the frame to the arm. The rocker's holes are read off the bushings and washers in them when the rocker has them as separate pieces: the shock's and the dog-bone's ends take the holes they reach (they may share one), and the pivot is the free hole the swingarm or the frame holds. A dog-bone's eyes are read from its round ends. With the Dog-Bone filled and the Rocker slot empty, step 2 looks for the rocker round the dog-bone's end: an object of its own goes in at Find Hardpoints, and a rocker still inside another part's mesh (the swingarm's, say) gets Split Rocker Out, which makes it an object of its own, called Rocker, where it is. The picture button on the header of the Rear Suspension slots opens a labelled picture of a shock and its linkage, and the one on the Drive Chain fold in the Parts map a picture of the chain and its sprockets, each in a window of its own to zoom and pan.

When something is wrong with the linkage, the box says why, with the markers left in place to fix. Wherever the linkage can still move, your parts are rigged anyway and the errors stay in red under Rigged anyway until they are fixed, while the physics keeps Built-in's geometry; where it cannot move at all, the car is drawn Built-in. The errors: parts missing (an upright that nothing holds), links that fight each other, a linkage that cannot reach the car's bump or droop travel, or a shock too long for the travel — one whose body alone is longer than the shock would have to be at full bump. Warnings that do not stop it: no tie rod (the wheel's toe is held straight), a tie rod that cannot turn the wheel to full lock, a shaft that would pull out of its body at full droop, or a shock modelled as one object (it is aimed between its eyes but cannot telescope).

Physics From Model (on by default) also drives the car on the geometry you modelled. Find Hardpoints and Rebuild sweep the linkage through its travel, roll and steering and hand the solver what it gives — roll centres and how they move, camber gain and the bend of the camber curve, bump steer and rear roll steer, anti-dive and anti-squat, kingpin, caster and scrub radius, and how much the springs and dampers stiffen through bump as their motion ratios change. On a motorcycle the rocker linkage's leverage gives the rear its rising rate. The numbers are listed in the Rig tab with small curves of camber, toe, motion ratio and leverage from full droop to full bump; check that they look like your car. A number outside the range a real suspension has is listed as a warning and the setting is used instead. The spring rates themselves still come from the settings — a model cannot say how stiff a spring is — and so do static camber and toe. Turn Physics From Model off to drive on the suspension settings while keeping your parts rigged.

From Model draws the wheel at the camber and toe you modelled; the Camber and Toe settings still set what the tyres run on. A hub moved by hand carries its knuckle straight up and down rather than along the linkage's arc, so the ball joints can come a millimetre or so off their arms until the next drive. Show Hardpoints hides the markers. Switching back to Built-in, Remove Rig and Reset Car all put every part back where it was.

Your Own Parts

Suspension units

From Model's slots come in units, drawn in step 2 as a map of the vehicle seen from above, as the Parts map draws its wheels: a cell for each corner of a car or truck where it sits (Front Left beside Front Right once the sidebar is wide enough, one under the other in a narrow one), each axle's cell (Front Axle, Rear Axle) between its corners and the next, and Rear Suspension 1 on a motorcycle. A second shock or a set added at a corner is a smaller button inside that corner's cell. Click a name and its slots show under the map, and step 4's Hardpoints list holds that unit's markers alone. Each cell says how many of its slots are filled (5/5) and has a tick when they all are, a dot when some are, and a red mark when Find Hardpoints fell back to Built-in over it. Add and Remove sit under the map; rename the picked unit in the field at the top of its slots.

+ adds a second shock: on a motorcycle Rear Suspension 2, the other side of a twin-shock bike; on a car or a truck a shock unit at the corner picked on the map (Front Left Shock 2), for a second damper at a wheel. It has slots of its own — Shock Body, Shock Shaft, Spring, and the Shock Reservoir on a bike or a Bump Stop on a car. Find Hardpoints rigs it like the corner's own shock: its top eye on the body or frame, its bottom eye on whatever it sits on (the swingarm; an arm, the knuckle or the axle — or the body when it is bolted to the Sub-Frame, and then the shock stands still and the springing is read off a shock that moves), telescoping as the wheel moves, its spring between its seats, and its length checked against its stroke over the travel. The rocker and dog-bone stay with Rear Suspension 1. An axle takes no units, so + is greyed with an axle picked. Assign by Name puts a second shock it finds into a unit you added for it; it never adds one. + also adds one of Your Own Parts, which are rows of the same list.

+ also adds All Slots Again: another whole list of the picked corner's (or axle's, or a motorcycle's rear) slots, Front Left 2, for a part modelled as more than one object — an arm and its bushes, a knuckle and its dust shield, a shaft and its boots. Nothing in a set is read for hardpoints, so the first list still decides the linkage: each part in a set moves exactly as the part in the same slot of the first list does, turning, stretching or spinning with it. A slot whose first-list slot is empty has nothing to follow; Find Hardpoints says so and the part stays on the body. Assign by Name puts a second part for a slot that is already filled into a set you added; it never adds one. − removes a set and puts its parts back.

− removes the picked unit or own part, and hangs its parts back where they were; a corner, an axle and Rear Suspension 1 are the vehicle's own and stay. Double-click a row to rename it: the name is used in the list, the report and the Hardpoints list. The physics is unchanged: the spring and damper rates come from the settings, and Physics From Model reads the rear's rising rate off Rear Suspension 1.

Anything else your model carries that should follow the suspension — a brake-line bracket, an ABS sensor, a CV boot, a second damper, a hose — goes under Your Own Parts, as many as you like, with Built-in or From Model. Press Add (with parts selected, each is added), pick the part, say how it is fastened, and press Rebuild:

Rides

Fixed to one node (On) and moves with it.

Aims

Pivots on node A and points at its far end on node B: a rigid rod.

Stretches

As Aims, and it lengthens and shortens between them: a boot, a gaiter, a straight hose.

Bends

Rides node A with its far end hooked to node B, its middle bending between, as Loose Wires do: a hose, a cable.

Keeps Angle

Goes where its node (On) takes it but keeps the body's angle: a reservoir, a mud flap that hangs straight.

Squashes

As Stretches, keeping its volume: thinner as it lengthens, fatter as it shortens. A bump stop, a rubber boot.

Between

Moves part of the way from where node A would carry it to where node B would; With B sets how far (0.5 is half way). A clip on a hose, a guard between an arm and the knuckle.

The nodes are listed by name: the body, each hub (moves up and down, does not steer), knuckle (steers), wheel (spins), the swingarm, the fork top and bottom, the cab, the gearbox sprocket, and with From Model every arm, link, shock half, rocker, rack, bar and axle. The ends of an Aims, Stretches, Squashes or Bends part are read off its mesh and marked like hardpoints: drag them and Rebuild keeps them. If an end lands on the wrong node, the ⇄ button swaps them. A part already in a slot, or a node the rig does not have (an arm when From Model has fallen back to Built-in), is left where it is and the list says so.

Placing hardpoints

The Hardpoints fold lists every marker by name (FL lower ball joint, Rear: rocker pivot, your own parts' ends, the gearbox sprocket's centre). Picking one selects its marker; clicking a marker in the viewport opens the Suspension section at its unit, with this fold open, and picks it in the list. The padlock beside a hardpoint locks it: Find Hardpoints then leaves it where its marker is and reads every other one afresh. Then:

Pick on Mesh

Click your model: the hardpoint goes to the vertex, the middle of the edge or the centre of the face under the mouse, whichever is nearest (V, E or F keeps to one, A back to nearest; Esc or right-click stops). The rig's own colliders and proxies are clicked through.

Cursor

To the 3D cursor — with Shift+S you can put the cursor anywhere first.

Selected

To the middle of the vertices selected in Edit Mode, or of the selected objects.

Bushing Centre

Select a ring of vertices round a bush's bore, an eye or a bolt hole (three or more, in Edit Mode): the hardpoint goes to the centre of the circle through them, and the bore's size is reported.

X− X+ Y− Y+ Z− Z+

Nudge it one Step along the car's own axes (across, forward, up), however the car is turned in the scene.

Symmetric

On by default: a marker moved on one side moves its partner on the other, mirrored. Mirror copies the picked one across once.

Live Check

A moment after a marker stops moving, the linkage is solved again with the markers where they are, and drawn in the viewport: the links green, the ball joints' and wheel's paths over the travel blue — or red, with the reason in the panel and the viewport, when it cannot work. It is a check only; Rebuild rigs your parts on the markers.

Moving the gearbox sprocket's centre moves the point it turns about, not the sprocket. The ends of a Loose Wire are its own end points, so there is nothing to place for them.

A motorcycle has two more markers at the top of the list, on any rig, Built-in or From Model: the Swingarm pivot (a sphere) and the Steering head (an arrow up the steering axis). Move them with the tools above or drag them in the viewport; the rig follows at once, and your parts stay where they are.

• Swingarm pivot. Build Rig puts it at the front of the Swingarm Parts that run forward from the rear axle, so a dog-bone or rocker kept in the same collection no longer pulls it off. Put it in the pivot bolt's bore with Bushing Centre. The swingarm, everything on it and the physics' swingarm (its length and angle, so the wheelbase, the anti-squat and the chain lines) turn about it.
• Steering head. The fork, yokes and bars turn about the line the arrow draws, at the angle it points, and the lower legs and the wheel slide up it. Build Rig lays it along the fork tubes it finds in the Fork Top (the lower legs in the Fork Bottom when there are none), set back from them by the Yoke Offset: the yokes hold the tubes ahead of the steering stem by that much, and most axles sit further ahead again, so the line through the tubes is not the line through the axle. The Yoke Offset is under the Fork Bottom slot and in the box under the list; changing it moves the arrow, until you place the arrow yourself. Real yokes are 20–35 mm; a model whose head tube sits right behind the tubes wants 0. Move it onto the head tube and rotate it (R X) to lie along it, or select the head tube's vertices in Edit Mode and press Axis Through Selected. The box under the list gives the rake, trail and fork offset it makes; Use For Rake And Trail copies them into the bike's settings, which is what the physics steers on.

Where you put them is kept in the bike's settings and stays through Rebuild, Remove Rig and Build Rig. Reset puts one back where Build Rig works it out (the steering head back along the fork tubes, the Yoke Offset behind them, or through the front axle at the Rake setting when Build Rig finds no tubes). With a From Model linkage, press Rebuild after moving the swingarm pivot, as for any marker.

A rocker linkage can only go so far: past a point the rocker and the dog-bone come into line and lock. When the rear travel is set further than that, Find Hardpoints says how far the linkage does reach, in mm of bump and droop, so you can set the travel to it, or move the rocker's pivot, the dog-bone's far end or the swingarm pivot until it reaches.

Seeing the suspension move

The Rig tab's View section draws the suspension over the car in the viewport, in setup and while you drive or play a take back, for cars, trucks and motorcycles, Built-in or From Model. Four views, each switched on its own:

Point Paths

The path every moving hardpoint and the wheel centre take from droop to bump, blue through white to red, and through the steering lock on a steered corner, yellow, with a dot where each is now. A beam axle's Panhard rod and links ride the axle; a motorcycle's front axle slides up its fork and its rear swings on the swingarm, with the shock, rocker and dog-bone of a From Model linkage.

Geometry Lines

Front view: each wheel's line from its contact patch through its instant centre to the roll centre (labelled with its height), and the roll axis between the ends. Side view: the anti-dive and anti-squat lines from the patches to their side-view centres, labelled in percent, and the pitch centre where they cross. A motorcycle shows its steering axis down to the road (labelled with the trail), its swingarm line, the chain's top run, the instant centre they make and the squat line through it. The numbers are the ones the car drives on, moving as it moves: the roll centres migrate with the roll.

Force Arrows

At each corner the spring (green) and damper (orange) at the hub and the tire load (white) at the contact patch, as long as the force is: Arrow Scale mm per kN.

Travel Gauges

A bar beside each wheel from its droop stop to its bump stop, the white tick at ride height, turning amber in the last quarter before a stop and red in the last tenth, with the travel in mm.

In setup, Move By Hand moves the drawing: Travel puts every wheel up or down, Roll rolls the car (the right-hand wheels into bump) and Steer turns the steering. The drawn linkage moves through its travel; your parts and the rig stay where they are. Setup shows the static forces; a take recorded with Record Telemetry carries every corner's spring, damper and tire load, so a played-back take draws them too (one recorded before 2.97.0 draws the springs from their travel and no damper). Drawing only: it changes nothing the car does, and it is never rendered. All four views and the CG marker together cost about 1–1.5 ms a frame while driving.

Roll centres

With Roll Centres From Linkage on, roll-centre heights, jacking and weight transfer come from the linkage. Turn it off to set the heights yourself. Roll Centre Migration is how much they move as the car rolls.

Kinematics

With Kinematics From Linkage on, the rest of the geometry comes from the linkage too. Turn it off to give the car its own; the values start from the linkage's, so nothing changes until you move one. The drawn arms follow them.

Anti-Dive / Anti-Squat

The share of the braking or driving weight transfer the links carry instead of the springs, at ride height. 100 % stops or launches the car flat. It falls as the car dives or squats and rises as it lifts, because the arms' pivot point moves with the body; caster grows as the nose dives for the same reason.

Camber Gain Front / Rear

How much of the body's roll the links take back out of the wheels: 1.0 holds the wheel upright, 0 lets it lean with the body.

Roll Steer Rear

Rear-axle steer per unit of roll. Positive steers the rear with the corner (understeer); a semi-trailing arm is negative.

Bump Steer Front / Rear

Degrees of toe-in per metre a wheel rises; negative is toe-out. Production fronts run about -2 to -10, which toes them out as the car dives and steers a rolling car slightly out of the corner; rears run 0 to +4. A live axle or twist beam has none.

Springs and dampers

Spring rates, damping ratio, anti-roll bars, and bump and droop travel. The Suspension preset (Comfort, Sport and so on) sets them all at once; Comfort Firmness leans it either way.

Every built-in car has a chassis of its own, and Apply Preset Chassis puts it back: springs, bars, dampers, linkages and lock, solved for the car's weight. The read-out under the springs and bars gives the ride frequency front and rear and the roll per g they make.

Damping Ratio is the mean of bump and rebound against critical damping. Road cars run about 0.3–0.45 and track cars 0.5–0.7; the default is 0.45, and each preset carries its own. 1.0 settles the body without any overshoot but passes more of every bump into it. Rebound / Bump sets the split, about 2:1 on a road car.

Past the Damper Knee (0.1 m/s of shaft speed by default) the valves open: bump damping drops to High-Speed Bump of its low-speed rate and rebound to High-Speed Rebound. Body roll and pitch stay under the knee; potholes and kerbs go over it.

Separate Rear gives the rear its own bump and droop travel, damping ratio and rebound. Off, the rear uses the front's settings.

At the end of the bump travel the wheel meets a foam bump stop. It is touched a few millimetres before the end and stiffens over the first 20 mm, as a real one does, rather than coming in all at once.

Tire enveloping

Contact Patch, Carcass Wrap and Tire Stiffness let the tire wrap over a kerb instead of hitting it like a solid wheel. Tire Stiffness is the tire's own spring, in series with the suspension's, and each wheel has its mass, so a wheel hops on a rough road at about 11 Hz as a real one does.

Kerb contact

Kerb Contact, under Tire Enveloping, lets the tires feel a kerb's edge. It is on by default (since 3.16.0). Off, a tire climbs a kerb by having the road under it raised: nothing pushes back, so the climb costs no speed, a kerb taken at an angle is climbed as if square on, and at speed the tire can be driven onto its rim. On, the tire meets the edge where a round tire does, a hand's breadth ahead of the contact patch, and is pushed along the edge's own normal:

• Slowly, it climbs on the tire's grip. The tire's drive force pushes along its tread, and at the edge the tread runs up the wheel's circle, so a driven wheel lifts itself for as long as its grip is worth the edge's angle: about a third of the wheel's radius from a standstill (10 cm on a Golf). A two-wheel-drive car stalls against anything taller and needs momentum to get up it (a Golf at 10 km/h gets up 20 cm). A four-wheel drive pushes each axle up its edge with the other and crawls up steps to about 0.85 of the wheel's radius (35 cm on a G63). A truck with only its rear axles driven stops against a 30 cm step from a crawl.
• Square on at speed, it is a hit through the suspension. The kerb costs speed (about 2 km/h for a 10 cm kerb at 30 km/h) and the tire's peak load stays a few times its weight instead of spiking off the rim.
• At an angle, it pushes the wheel sideways. The shallower the angle, the more of the push is sideways: a 15 cm kerb at 10° steers the car off it instead of being climbed.
• On a motorcycle, a shallow kerb is dangerous. Square on, a bike rides up a kerb as a car does, with a harder hit. Taken at a shallow angle, the edge pushes the front tire along it: a 15 cm kerb at 10° pushes the bike off it at walking pace, and a 10–15 cm kerb at 20° can put it down at 20 km/h. Cross kerbs as square as you can.
• Too tall, it stops the wheel. An edge level with the hub gives no lift at all, and the tire's grip gets no purchase on a face above the hub, so nothing taller than the wheel's radius is climbed.

Cars, trucks and motorcycles. Turn it off to get the old contact back (a car preset saved with it off turns it off again when loaded). The kerb has to be in the collider set. It costs about 0.02 ms per wheel per physics step on open road and about 0.08 ms while a tire is touching an edge.

Tires

Tires, at the top of Tires & Brakes, picks what the car is on: Stock is the tire it came on, at its own grip, and the rest — from Race Slick and Track through Summer, All-Season and Touring to Eco, Winter, All-Terrain and Drag Radial — scale that grip, how sharply it builds and how it lets go. ABS and traction control follow the tire. Tire Stagger is the rear tread width over the front: a wider tire is rated for more load, so the wide end grips harder at the same load.

Steering

Max Steer

Lock at the front wheels. A car set up to be held sideways runs 50 degrees or more.

Steer Speed / Steer Return

How fast the wheel turns and self-centres. Steer Speed gives the same road-wheel rate under every Speed Law, so the wheel arrives when asked at any speed.

Ackermann / Caster Feedback

Steering geometry and self-aligning feel.

Brake Toe Front / Rear

Toe each wheel takes per kN of its own braking force, through its bushes; positive is toe-in. Small on real cars and either sign; 0 is rigid.

Speed Law

How lock is scaled with speed, so the same input doesn't ask for the same angle at 20 mph and 120. Parking-speed steering stays full under every law.

Steering Axis

Kingpin inclination, caster and scrub radius — read from the linkage by default. The line underneath shows what is in force.

Toe, camber and ride height, front and rear, update live while you drive. Compliance Front and Rear are how far the bushes let the wheels steer under side force — most of what makes a road car understeer.

Show Suspension draws the linkage in the viewport. Rebuild Suspension remakes the parts after you change the architecture.

Driver aids & ignition

Assists

ABS, traction control, stability control, launch control, cruise control and a rev limiter. Each is modelled, not faked, and each can be switched off. ESC Strength sets how hard stability control steps in.

Driver Aids is in sections — Grip & Stability, Cruise Control, Follow Path, Ignition, Rev Limiter, Launch Control and Cluster Warning Lights, and Riding on a motorcycle — and each folds away on its own. An aid with a switch carries it in its header, so you can see it is on with the section closed, and a warning inside shows as an icon on the header.

Cruise control

K sets and cancels, = and - adjust, J resumes. Braking, the handbrake or leaving Drive cancels it. It won't engage below its minimum speed.

Ignition

Start and stop the engine with Alt + Shift + S, or hold L1 + R1 on a controller. It only switches off with the car stopped. Engagement Inhibit refuses a gear above a set rpm. The other settings shape the start: crank time and rpm, the flare as it catches, the fast idle afterwards, and the run-down when switched off. Battery and Condition let a tired car struggle to start.

Cold Start (off by default) gives the engine a temperature: it warms over Warm-Up Time while it runs and cools slowly while off. Cold, it idles higher and less evenly, its mechanical noise is louder and the exhaust is a little louder while the catalyst heats.

Rev limiter and launch control

The rev limiter has a soft and a hard style and works in Park and Neutral only — in gear, the road sets the revs.

Launch control arms when you hold throttle and brake at a standstill, and launches when you release the brake. While it is armed it holds the car on its brakes at full pressure, as a real car's stability control does. On an electric car it holds the tires at their peak slip instead of a launch rpm.

Launch RPM

Where it holds the engine.

Launch Slip Target

How much wheelspin it allows.

Launch Squat

How far the rear sits down while armed, on top of the squat the brake hold gives. Off by default.

Launch Exit Speed

Where it hands control back to you.

Lights

Every section of Lights folds, and all of them start shut: click a section's name to open it. A section's + stays on its header, so a unit can be added with it shut.

Press Set Up Light Materials. It finds the emissive materials on the car and wires each one to the right lamp, so the lights use the materials your model already has.

Levels and timing

A brightness for each function — running, brake, DRL, headlight, reverse and indicator — plus flash rate and rise/fall times, so a filament lamp glows up and fades rather than snapping. Indicator colour is set as a temperature, front and rear separately. Low and high beams are set in watts.

The indicator colour looks the same whether a lamp's material uses a Blackbody node or a plain colour.

Sequential sweep

Modern indicators fill from the inside out. Sweep Time is how long the fill takes, Sweep Edge how soft the moving edge is. Welcome Sweep plays it once when the car is unlocked. Measure Sweep Axes works out which way each lamp sweeps; a centre lamp opens from the middle out.

Lamp groups

Headlights, tail lights, separate indicators, low beam, high beam and reverse. Each group can double as an indicator, be sequential, and join in on hazards. Sweep ready means the axes are measured and the sweep will run.

Tire smoke & tire marks

Tire smoke

The FX tab holds three kinds of smoke, and each works on its own, with the other two on, off or never set up:

• Live Smoke — a light cloud drawn while you drive. Off on a new car; tick it to use it.
• GPU Accelerated Smoke — real-time smoke on the graphics card, from the tires and the exhaust, with backfires that shoot flame out of the pipes on a lift. Emission Arc is how much of each tire smokes, and each press of Add Smoke Emitter puts one more exhaust emitter on the car, selected and ready to move. Under its domain's Look, Detail adds wisps finer than the grid that move with the smoke (viewport only), and Rays on Auto draws at half resolution when the smoke fills much of the view. The car's domain slides back along the car's path by its Trail, so a run or a drift keeps its smoke further behind the car.
• Mantaflow Smoke — Blender's own smoke simulation, for the final render. The settings below are its.

All three follow tread temperature, not slip directly — so a long slide smokes harder at the end than the start — and each has its own Tread Heat.

Heat

Heat Buildup and Cooling set how fast the tread heats and cools. Smoke Point is where smoke starts, Onset Width how sharply, and Afterglow how long it lasts once you're off it.

Emission

Density, spread around the contact patch, how much the car carries along, randomness and buoyancy. Smoke settles on the road surface instead of sinking into it.

Wheel Flow

Adds the air the wheel moves — a jet off the contact patch and a vortex around the wheel — so smoke rolls like it does behind a real car.

Colliders and Domain

Colliders wire the tires (and optionally the body) into the smoke domain so the plume breaks around them. Domain holds resolution, dissolve time and vorticity.

Record Tire Smoke keys the emission with the take, so a replay smokes where the drive did. Readouts marked as guessed settle once a take has been driven.

Tire marks

Every simulated car lays its own marks, so a race leaves the whole field's lines on the road.

The mark

Darkness, Onset (slip needed before it shows), Detail, Width, Tail Fade, lift off the road, and how overlaps combine. Burnout Rate, Heat Response and ABS Chatter add marks from burnouts, hot tires and pulsing ABS.

Look

The surface (asphalt, concrete…) and everything that makes rubber read as rubber: opacity, edge softness, profile, striations, break-up, roughness, sheen and relief. Refresh Look rebuilds the material after a change.

• Clear On Record — wipes the road when a take starts.
• Join Tire Marks — merges the marks into one object.
• Clear Tire Marks — removes them all.

Engine sound

The engine is synthesised from the simulation's own rpm, load and throttle — there are no samples. Live Sound is what you hear while driving.

The tone is a Harmonic Stack: the engine's orders, voiced by hand for each engine layout, summed and sent through the exhaust settings below. An electric car has Electric Sound instead: Natural, Sport or Silent.

Presets

Whole voices to start from, and where your own are saved.

Engine

Layout, cylinder count, firing order and the spread that gives a V8 its lope and a flat-six its wail. Cylinder Imbalance makes no two cylinders fire quite alike, which gives the note its half-orders. Induction Honk is the intake's resonance: the engine comes on song where the firing order meets it, and the naturally aspirated presets set it. Mechanical is the block's own noise: Valvetrain ticking, Injector Tick and Chain & Belt Whine. No built-in preset sets the valvetrain above 0.2 or the injectors above 0.15; the sliders go to 2 for a race engine.

Engine Braking

What it sounds like off the throttle. Load Dynamics is how much quieter a shut throttle is than an open one: 0 the same, 1 about what a real exhaust does. Full throttle is the same at any setting.

Forced Induction

Turbo or supercharger whine, spool, blow-off and flutter. Anti-Lag (off by default) keeps a turbo on boost off the pedal above Active From, with Bangs from the exhaust.

Exhaust

Pipe length and reflections, the overrun, and the layout: Crossover (true dual, H-, X- or Y-pipe), Headers per bank or 180 degree, Header Mismatch and the firing order, the Muffler (stock, chambered, straight-through or turbo-style) and a Drone Resonator tuned to a cruising rpm. Boxer fours and flat sixes have layouts of their own. Exhaust Tone adds what the hand-voiced orders leave out: Upper Orders (the harmonics above them, up to about 9 kHz), WOT Steepening (a sharper pulse under load), Pulse Rasp (the blowdown's turbulence) and Shell Ring (the pipe walls, and a heat shield that rattles). Limiter Type is how the rev limiter sounds: Fuel Cut, Ignition Cut (most cuts end in a bang) or Soft Cut (a ragged hold). Misfires is how loud a lean misfire is, with an afterfire now and then.

Active Exhaust Valve

Opens a bypass under load, like a modern car. Valve Button is the console button: Auto, Open or Shut, and V steps through them while driving. In Auto, Close Delay keeps it open after a lift, so you hear the overrun.

Mix

Levels of every layer: engine, exhaust, starter, tire screech, rolling noise and the drive-by whoosh. Stereo Image places the engine bay and the tailpipes where they are in the picture, so a car crosses the view as it passes. Inside the car, Sound Deadening and Cabin Tone give the cabin's muffled, bassier sound. A bake that follows the scene cameras hears both, and writes a stereo file.

Distance Falloff

How the car quietens with distance from the camera, and the Doppler as it passes. Air Absorption takes the top off a distant car, as air does.

Match Tone To Vehicle (in the Vehicle panel) points the sound at the car's capacity, cylinders and redline — the fastest way to a sound that fits.

Turbo flutter

Lift off at boost with no blow-off valve and the turbo flutters — "stu-tu-tu". It also fires on every upshift under power. Release, under Forced Induction, sets its character: 0 is a soft, voiced "tu"; 1 is a sharper burst of air. Default is 0.65.

Overrun pops

Pops and crackles on a lift, densest right after you lift and tapering off. Pops sometimes come in short runs, an upshift under power gives a "brap", and pops follow the Doppler like the rest of the car.

The settings are under Exhaust:

Pops Per Second

How busy the crackle is.

Pop Duration

How long the pops go on after a lift.

Bang Size

How big the pops are.

Overrun pops are off until you switch them on.

Cylinder on Demand

A V8 cruises as a four at light load and switches back to all cylinders as soon as you press past about 30% throttle. The car decides when — warmed up, in Drive, at a light pedal and at cruising speed and revs — and the panel says what it is doing ("Running on 4 of 8"). A recorded take bakes it as it happened. Off until you switch it on.

Ground & collisions

Ground Z is the height of the road. It stays where you set it — building a rig never moves it.

Ground type

• Flat Plane — an infinite level surface at Ground Z. Fast, and right for most shots.
• Mesh Terrain — the car follows hills, ramps and banking, and can leave the ground. Any mesh in the collider collection works, high or low poly. Where the terrain has nothing under the car — past its edge, or below all of it — Ground Z is the fallback: the wheels and the body stand on a level floor there.

With Solid Colliders on, the body and wheels hit walls, kerbs, tunnel roofs and anything else with faces.

Wheel colliders

Each tyre gets a hidden collider when the rig is built (Wheel Colliders, under Chassis → Tires & Brakes), which is what the car's wheel radius and width are measured from. Detail sets how many sides it has (32 as before, up to 256) and Follow Tyre shapes it to your tyre's own section, rounded shoulders and all, read off the wheel mesh, instead of a plain cylinder. Both are drawing only: the physics works its contacts out from the radius and width, never from the collider's faces, so the car drives exactly the same and more detail costs nothing while driving (a refit takes a few milliseconds per wheel; 80 ms at 256 sides following the tyre). With Follow Tyre the panel shows the crown radius your tyre has against the one the physics rolls on.

Body proxy detail

Proxy Detail sets how closely the collision shape follows the bodywork, and so how much gap is left when two cars touch. Higher is tighter but costs more bake time and a little per step. Drop it on a big field; raise it if cars stop with a visible gap. The readout under Build Body Proxy shows the numbers.

Deformation

Experimental — turn it on in the add-on preferences and it appears under Colliders.

Dent The Bodywork

Impacts crumple the car where it was hit, in the direction it was hit, scaled by mass — the hatchback that hits the van is the one that bends. Damage builds up over a drive and carries into the next one. Straighten Panels or Reset clears it. Recorded takes key the damage on the frame it happened, and the bent body is kept for rendering.

Squash The Tires

Flattens the contact patch and bulges the sidewall under load; softer tires deflect more. Squash Limit is the rim. Squash Reach is how far up the wheel the flattening goes — lower it if the rim starts to move, raise it for a tall sidewall. Squash is recorded with the take.

Cars hitting each other

Cars Hit Each Other makes the cars in the scene solid to one another. It's on by default and works on both ground types. See Multiple cars.

Paths & autopilot

Point Follow Path at a curve and the car plans the whole line up front: it brakes before a corner rather than in it, and if it can't make a corner it goes slower there for the rest of the lap. The settings are at the bottom of the Driver Aids panel.

Settings

Speed Limit

Top speed on a straight. Corners set their own speed.

Pace

How hard the driver uses the tires. 1.0 is the limit; above it asks for grip the car doesn't have.

Look Ahead

How far down the road it aims. Higher cuts corners more.

Line Offset

Drive to one side of the line — for a second car on the same path.

Reverse Direction

Drive the curve the other way.

At The End

Stop, keep driving, return, or loop.

Road width

By default the car drives the exact line you drew. Set a Road Width and the path becomes the middle of a road — calmer, and far smoother on a hand-drawn curve. Use The Road lets it take a racing line (out wide, apex, out again). It only gains time on a wide road, so it's off by default.

Drift

The Drift slider lets the car drift through corners on a path — 0 grips, 1 slides as much as it can.

• Very powerful cars can spin at middle Drift settings. Try Drift at 1.0.
• Very grippy cars may not break loose at all.
• Raising Pace does not help it drift.

Path Assist

For shots where the car must go exactly where you told it rather than where the physics allows. At 0 the tires decide everything. Turn it up and the car's position, heading and slide are eased toward the line; at 1 it's on rails and never misses a corner.

• Engine, gearbox, suspension, wheels, sound and lights all behave normally at every setting.
• A real impact drops the assist for about 1.5 seconds, then the car drives itself back onto the line.
• In a race it applies to the whole field — nobody spins or runs wide, so order is decided by pace. Cars still avoid each other.

Path Assist is in Driver Aids, on each Garage slot and in the race settings, next to Drift.

Avoiding obstacles

With Obstacle sensing on (an experimental feature), a car on a path steers around something in its way and holds the swerve until it's past.

Multiple cars

Garage → Cars In This Scene lists every car in the file. Each keeps its own settings, engine, camera and mounts.

• Make Active — take control of a car.
• Store — save its current state.
• Reset All — put the whole field back to the start, or to before the last drive.
• Take Over — switch cars, even mid-drive. The car you leave carries on under its own driver.

What the other cars do

Parked

Sits on its springs and reacts when hit. Can have its engine running.

Follow A Path

Driven round a curve by the autopilot.

Follow The Active Car

Holds station on you — behind, behind-left/right, alongside, or in front, at a set gap.

Towed

A trailer, coupled at its hitch to the vehicle in Towed By. It rolls, swings and brakes behind it.

Not Simulated

Stays exactly where it is. Costs nothing, but can't be hit. Use Parked for an obstacle you want to shunt.

Towing a trailer

1. Rig the trailer like any vehicle: Find Parts, then the Car trailer or Semi-trailer preset, then Build Rig. Rig the vehicle that pulls it too, a truck preset for a semi.
2. Set the trailer to Towed in its row of Garage → Cars In This Scene.
3. Towed By picks the vehicle that pulls it. Left empty, it is whichever car you drive.
4. Place Hitch puts the coupling where the two meet: on the fifth wheel for a semi-trailer, at the drawbar tip for a ball. Stand the trailer hitched first, and move the Empty if it is off.
5. Drive the vehicle in front. The trailer's brakes follow it.

Four switches set how much the field joins in: Simulate Other Cars, Record Them Too, They Lay Rubber Too and They Make Noise Too. Markers float a coloured tag over each car; click one to switch to it.

Contact between cars

Cars are solid to each other. A shunt pushes the car ahead; a rub scrubs speed off both. Heavier cars move lighter ones more. A car needs a body proxy to be hit. Turn it off with Cars Hit Each Other (Ground & collisions) for a ghost lap or a camera car.

Recording & rendering

Record a take

Press Drive + Record to drive and record in one go. The drive is saved as keyframes: position, wheels, suspension, lights, camera and lens, plus rpm, gear, throttle, brake, speed and slip. Tire smoke and deformation are keyed too. Takes are filed, so you can keep several and switch between them.

A take is ordinary Blender animation — edit, retime or layer it. The add-on doesn't need to be running to play it back.

Bake the audio

The renderer can't hear the live engine, so bake it for any render with sound.

1. Drive with Drive + Record.
2. Press Engine Sound → Bake Audio For Render. Every recorded car is baked from its own engine settings, to its own file, on its own sequencer channel.
3. Render to a movie format with an audio codec selected.

The Garage

The browser at the top is your library of saved cars, shown as previews, a grid or a list. Spawn Vehicle drops the selected car into the scene, ready to drive, at the 3D cursor or wherever you choose.

• Save As New Preset — saves the whole car (geometry references, tuning, ECU tables, engine tone, lights, camera mounts) with a thumbnail.
• Update — overwrites the preset the car came from. Greyed out for a spawned car; save it as new instead.

The active car's name is at the top of the sidebar. Click it to rename the car: a small box opens with the name selected; type the new one and press Enter. The new name is what the Garage and Cars In This Scene show.

Presets live in a folder you choose, so you can move, share and back them up like any other asset. Cars In This Scene is covered in Multiple cars.

Experimental features

Some newer and heavier features ship switched off. Turn them on with Experimental Features in Preferences → Add-ons → Vehicle & Engine Simulator. Until then they are hidden and inactive — a file saved with one enabled won't run it on a machine where the switch is off.

• Race mode
• Slipstream
• Obstacle sensing
• Body and tire deformation
• Tire roar
• The engine fault lamp
• Modifier suspension

Troubleshooting