Build it yourself
Every part starts on the shop floor. Fit each one in the order a technician would, and the app tells you when you get it wrong.
New The clutch, from pedal to flywheel 
Learn how cars work in interactive 3D
Seven real car systems, built part by part. Turn them, take them apart, run them and put them back together on iPhone and iPad.
Scan with your iPhone camera to open the App Store
In the app
Take it apart. Make it move.
Every system is a working 3D assembly. Explode it to see each part, tap a part to learn its job, then run the live test and watch the whole thing respond.
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Explode any assembly
Pull a system apart into its parts and see how they fit together.
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See inside a running engine
A four-stroke cutaway with every valve, piston and cam live.
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Run the brake test
Squeeze the caliper and read the clamp force as it builds.
Seven systems
How cars work, one system at a time
Each guide answers one question in plain words, with a diagram you can drive. Then open the same system in the app and take it apart.
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Engine
How does a four-stroke engine work?
A four-stroke engine makes power in a cycle of four piston strokes, which take two turns of the crankshaft.
Read the guide -
Clutch
How does a car clutch work?
A clutch connects and disconnects the engine and the gearbox (transmission).
Read the guide -
Suspension
How does a MacPherson strut work?
A MacPherson strut is a suspension design in which one unit, a coil spring wrapped around a damper, locates the top of the wheel and carries the car's weight.
Read the guide -
Wishbone
How does double wishbone suspension work?
Double wishbone suspension holds each wheel between two A-shaped arms, an upper and a lower, which pivot on the body and meet the wheel's knuckle at ball joints.
Read the guide -
Brakes
How do disc brakes and ABS work?
Pressing the brake pedal pushes fluid to a caliper at each wheel, where a piston squeezes two friction pads against a disc that turns with the wheel.
Read the guide -
Steering
How does rack and pinion steering work?
In rack and pinion steering, the steering column turns a small gear, the pinion, which meshes with a toothed bar, the rack.
Read the guide -
Drivetrain
How do a CV axle and a differential work?
In a front-wheel-drive car the gearbox turns a differential, which splits the drive between two half-shafts, one to each front wheel.
Read the guide
Tap a part, learn its job
Every part tells you what it does and how it fails
Damping
Strut Damper
What it does
The hydraulic heart of the strut. As the suspension moves, its piston forces oil through small valves, converting the spring's oscillation into heat so the car settles after one stroke instead of bouncing. In a MacPherson design the strut is also a structural member that locates the wheel.
Spec sheet
- Type
- Twin-tube, gas
- Stroke
- 140 mm
Build and Quiz
Then put it back together
Prove you know it
Find the part on the 3D model, then put the whole assembly in fitting order. Your best scores are kept.
Who it's for
For anyone who wants to understand the machine they drive
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Curious drivers
Understand what the garage is talking about before you hand over the keys.
Learn car mechanics -
Students and apprentices
See the parts your IMI, City & Guilds or ASE course describes, working.
For students -
New technicians
See how each assembly comes apart and goes back together, in workshop order.
The seven systems -
Teachers
Show a class what a textbook diagram cannot, on an iPad and a projector.
For teachers
Questions
Questions people ask first
What is 3D Mechanic?
3D Mechanic: How Cars Work is an app for iPhone and iPad that teaches how real car systems work in interactive 3D. It has seven systems, from the MacPherson strut to the clutch, with parts you can tap, live tests, a build mode and quizzes.
Which systems does it cover?
MacPherson strut suspension, double wishbone suspension, disc brakes with ABS, rack and pinion steering, the CV axle and open differential, a four-stroke inline-four engine, and a hydraulic clutch from the pedal to the flywheel.
Is 3D Mechanic on Android?
Not at the moment. It is made for iPhone and iPad only.
Does it work offline?
Yes. Once it is installed, everything works without an internet connection, so it is fine on a plane, in a workshop or in a classroom with poor Wi-Fi.
How accurate are the models?
Each system is a generic compact front-wheel-drive car part, modelled piece by piece with a real layout, and the numbers are teaching values that stay consistent across the app. It is for general education, not a repair manual: on a real car, follow the maker’s procedures and torque values.
See how a car works, part by part
3D Mechanic for iPhone and iPad.
Scan with your iPhone camera to open the App Store
