- Since the 1930s, every car has started as a full-size clay model before being manufactured.
- These large clay models can cost automakers hundreds of thousands of dollars.
- We explore why, in 2022, clay modeling is still a crucial step in the design process.
Narrator: Every automobile you’ve ever seen once started as a full-size carefully sculpted clay model. Constructing these models can cost automakers hundreds of thousands of dollars per vehicle. With major advancements in 3D imaging and virtual-reality technology, why are automakers still investing so much money in giant hunks of clay to design their cars?
James Gillies: Well, typically inside a clay model, it’s just usually a steel frame with your wheel hubs attached to it. On top of the steel frame, it will get blocks of foam glued to it. And then from there we’ll pack 1 to 2 inches of clay on that, which will be machined, which then we start sculpting on or refining the design.
Narrator: From there, the details vary based on how intricate of a model it is. Still, a full-size clay model may feature $20,000 worth of materials. And the hours of labor contributed by digital designers, sculptors, and milling by CNC machines add up. Depending on how many adjustments are made to the model, it can take a couple of years to finalize.
The origins of clay modeling can be traced back to General Motors in the 1930s. Harley Earl, head of GM’s styling studio, was the first to turn sketches into full-scale models using malleable clay. It changed the industry by how much it simplified and sped up the design process. Designers could now visualize shapes and forms that were difficult and time-consuming to create in steel. But in the 21st century, the age of all things digital, why is clay modeling still worth it?
Robert Fallon: As much as you can do on a screen digitally, mathematically it’s still in essence a 2D image. So at some point in the process very early on, we need the 3D image that we can see, we can touch. We can evaluate proportion. It’s very difficult to evaluate proportions of a car on a screen. And the thing is, with a 3D model, you can’t lie. There’s no cheating. It is what it is. What you see on the tube or on the screen, it might look great, even in VR, for example, but when you mill it out, there’s always a lot of surprises. For example, certain lines, on a digital model, for example, they might look sweet, but when it’s milled in full size, they might hang and the proportions might look wrong. Like I said, you can’t lie with 3D.
Narrator: Clay models can also be useful for aerodynamic testing. In the wind tunnels, where engineers evaluate a car’s drag, or how easily it passes through the air around it, they’re the perfect time-saving tool.
Robert: Well, ultimately, you need to lower the drag coefficient. Particularly in an electric car, the lower figure, the better, obviously, because it’s more efficient. And the thing is, with the wind tunnel, it’s very expensive to rent per hour. It’s thousands and thousands of dollars sometimes. So we do work on a clay model in the wind tunnel so we can quickly implement changes, because time is money, basically. And although we have computer models for aerodynamics, we still need to double-check to see, to be 100% sure.
Narrator: Perhaps most importantly, what clay models reveal that digital imaging doesn’t is what the vehicle will look like in natural light. One of the crucial tests is taking it outside, where designers can see what the car will look like where it will actually be driving. It’s here that they can see how the sun bounces off of its curves and whether it looks like they imagined or just plain wrong.
This doesn’t mean clay models are an ancient design method that hasn’t changed. Decades ago, when the entire model had to be developed by hand, it could take weeks upon weeks to create a model to begin working with and testing. Today, with CNC machines and data-driven systems, a detailed model can be milled overnight for sculptors to begin working on. Just like the entire car industry, it’s evolved to be faster.
Jenny Ha: In our design process, too, we make many variants quickly in digital data and quickly review in VR every single week. But whenever we need a validation, we always mill it out again in clay overnight and check it again. If it needs some handwork, we do it quickly.
Narrator: Despite how much quicker computers have made carving whole cars out, there’s still an area where human modelers have the advantage: finesse. Sometimes a detail on a car’s body may need to be changed as little as a millimeter. An edit like this can be tedious, but using the malleable clay allows designers to visualize and make multiple changes with real-world proportions, something a computer rendering can’t compete with. Even if digital technology continues to make car design less labor-intensive, only clay models finished by human sculptors will help car companies achieve what they’re aiming for.