I designed and 3D printed a road-legal car. And yes, it really is road legal and registered in California.

The Body

• Designed in Fusion 360’s Form environment

• Refined with FEA and AirShaper CFD analysis to improve aerodynamics

• Printed as a thin shell (~8 mm thick) in PETG

• 3 printers running 24/7 with print automation took about a month (real time) to print it

• Over 600 pieces, meticulously hand-assembled with heat staples

• Seams smoothed with fairing compound

• Carbon fiber applied to the inner and outer surfaces for strength and heat resistance: at least 1 layer everywhere, and up to 5 layers of 200 gsm in key structural areas

Drivetrain and Chassis

• Motor: 2014 Nissan Leaf EM57, a permanent magnet synchronous AC motor

  • 80 kW (107 hp)

  • 254 Nm (187 lb-ft) of torque, available from 0 rpm

  • 10,500 rpm max

• Gearbox: stock Leaf single-speed reduction gearbox (7.94:1) with integrated differential

• Battery: 2014 Leaf pack, 24 kWh lithium-ion, 360 V nominal, 48 modules (96s2p), air-cooled

• Controller: Resolve EV

• Layout: motor moved from the Leaf’s front-wheel drive to rear-wheel drive, powering the wheels directly through the stock gearbox and differential

• Suspension and steering: Mazda Miata (NC)

• Weight: under 2,000 lbs (estimated)

• Seating: centerline tandem

The Journey

This was a huge project. It went from ideation, 3D scanning and modeling, to a working drivetrain and chassis, to a 3D printed carbon fiber body, and finally through a crazy amount of DMV paperwork and hurdles. It’s done now, and the result is pretty awesome.

What’s Next

• Better surface finish for the body, either paint or a cosmetic outer layer of carbon fiber (this will probably take another literal 1000 hours of sanding to really perfect it)

• Custom CAN bus analog gauges for status

• Wider wheels with a bigger contact patch for more traction (it spins the tires easily!)

• Later, maybe an experimental self-driving module or a robotic arm attachment, to really make it a sci-fi dream

Follow the Build

I’ve posted clips and reels of the build on Instagram. Find all my socials here: kuehn.us

How I Split the Model

I split the model into easy-to-print, easy-to-assemble pieces with an outdated proprietary software. Since then, I’ve built my own version and released it publicly, so you can use it for your projects too. I spent a lot of time perfecting it, using AI tools to speed up development. It’s now one of the most reliable tools out there for large-scale 3D printing of shell models.

Section3D: github.com/k-kuehn/Section3D

Disclaimer: This model is provided “as is,” with no warranty or guarantee of any kind. If you print it or use it in your own project, you do so at your own risk. The designer is not liable for any damages, injuries or losses that result.