3D CAD: Computer-Aided Design For The A1 Sportback

source: Charlotte Seybold for Audi AG

Binary code meets human instinct: what happens when the power of 4,300 laptops is combined with human craftsmanship? That’s what author Charlotte Seybold explored in the Audi Designcenter. Now she’s lifting the veil of secrecy surrounding the debut of the Audi A1 Sportback.

Curiously, I open the door to the new C3 studio in the Audi Design department. Bright light streams from the neon lights, electropop gently wafts from the speakers. The room is full of designers, 3D CAD- form designers and clay modelers. CAD stands for Computer-Aided Design, meaning that the design phase is helped along by automated, digital processes. And then, there it is — right in the middle of the huge model studio: the Audi A1 Sportback. Made from light-brown clay, a special industrial plasticine mixture. Made just for me.

But why is there a need for a physical model during the digital design phase? Does digital design need to be made tangible? Equipped with these questions, I hurry through the hall to Markus Gleitz, the head of the Exterior Design CAD/Technology department. He and his colleagues are giving me  a chance to experience the digital design phase of the Audi A1 Sportback’s exterior up close.

Audi A1 Sportback: Digitization meets craftsmanship – the 3D CAD process

Markus Gleitz is standing on the other side of the studio in front of a big screen, known as the LED Powerwall. He explains the course of the design process to me: “The design process of a series model at Audi takes around 4.5 years and is made up of individual phases. Prior to beginning the digital design phase, we work together with experts from technical pre-development and marketing.”

And how do the Audi experts begin their work on the product design? “In the initial design phase, we define the first technical frameworks such as the hood’s elevation or the wheelbase.”

Within these requirements, the designers can let their creativity run free in the drafting phase. Sketches are made either traditionally on paper or digitally on a tablet. After the drafting phase, it’s time for the digital design phase, known as the C3 process for short – and that’s what they’re working on today. The three “Cs” stand for CAD, Concept and Clay shaping.

In the C3 process, CAD form designers transform the designers’ sketches into a 3D CAD data model. The data is displayed photo-realistically in real-time on the Powerwall. Digitization at its best. Soon afterward, a milling machine uses the data to create a physical clay model. It’s the perfect combination to make digitization tangible.

But one thing after another. Markus Gleitz takes me to the workplace of CAD form designer Harald Riedlmüller. His desk is located outside the C3 studio, with only a large glass front separating him from the studio. From there, he has a view of the complete C3 hall: the LED Powerwall and the clay models are always in view. He can also transmit his 3D CAD data from his desk to the huge Powerwall inside the studio – only 20 meters as the crow flies.

Designers and CAD formers use the Powerwall to evaluate the data on a 1:1 scale and check its consistency. Due to the high power of the computation cluster — essentially a huge computer network — designers can see immediately how their changes affect the digital model.

The 3D car is displayed photo-realistically and in real-time. Harald Riedlmüller shows me how to rearrange individual on the computer. I equip the Audi A1 Sportback with a broader tailgate and am amazed to see my draft appear on the wall in the studio. “With the 3D software, we can visualize any changes in terms of proportions, overhangs or shadowing very quickly”, Harald Riedlmüller says. This lets them detect possible discrepancies before the clay model is built — in contrast to their previous working methods.

3D CAD design: surprisingly realistic – photo realism within seconds

The computation cluster even makes it possible to create a photorealistic simulation of the 3D CAD data in real-time. As soon as I’m back in the hall, I find out what that means: a single mouse click transforms the CAD data into a photorealistic visualization of the Audi A1 Sportback in seconds. I have to admit: I’ve gone a bit too far with the tailgate.

A click later, the virtual version of the Audi compact car is in the Design Studio Peking. Harald Riedlmüller swivels around the model and takes a look at the A1 from above. Gigantic! Even the reflections in the paint are photo-realistically animated. The visualization software uses ray tracing, a vector-based rendering method that calculates optical effects such as light, shadow or reflection using correct physics and displays them accurately, taking into account the time of day. For perfect car design.

“Thanks to the high-tech visualization, we can digitally evaluate the design at a very early stage of the process.”

Markus Gleitz, Head of the department Exterior Design CAD / Technology

The computing power of the cluster is equivalent to around 4,300 notebook computers. Even dynamic driving footage and driving simulations of the models can be calculated and displayed on the Powerwall. Without the Audi A1 Sportback ever having been on the roads of Barcelona, I can watch it gliding along Spanish streets in the early evening — at 7 pm sharp. But of course, I still can’t touch it.

Is that the reason that the Audi A1 is still shaped from clay? “No, not only because of the haptics,” Harald Riedlmüller explains. “The Powerwall gives a really good impression of the vehicle. But nothing quite compares to the feeling of standing in front of a real model. Only then is the perspective realistic and lifelike for the human eye.”. The digital possibilities facilitate the production of life-size models. By constantly comparing the Powerwall with the clay model, the milling machines automatically change the clay model to reflect changes in the 3D CAD data.

That is, as long as enough material is available. Before the machine shapes my expansive tailgate, fresh clay has to be applied. That’s still done by people.

Hello, future! Virtual Reality in design

The Audi designers also have another tool available: VR glasses. “With the VR glasses, we can take a look at the model in 3D in a virtual simulation. The lifelike display of design models becomes even more realistic”, explains Harald Riedlmüller. “In the following years, VR applications will become a standard tool in the design process”, Markus Gleitz adds. But VR glasses will be able to do even more.

While the milling machine gets to work, we have time to take a look into the future. In the “holodeck” one floor higher, Audi designers are researching new virtual display options. There, with the help of VR glasses, they can view their 3D CAD models in a seemingly real virtual world. Multiple users can log in simultaneously and see each others’ avatars. In the foreseeable future, VR glasses will make it possible to hold design meetings across multiple continents. Then Audi designers from Ingolstadt, Beijing and Los Angeles could meet up as avatars in a virtual studio. And that’s when digital data will come to life: wired gloves with haptic feedback will make it possible to digitally touch the virtual models. There you have it: digitization you can touch.

The milling machine is finished by now. In just 15 minutes, it has implemented my changes into the clay model. Feeling a bit shy, I stroke the broad tailgate. Luckily, my changes can be reversed with just a few clicks. The design of the future is better left in the hands of designers and 3D CAD form modelers.