Tesla design head Fraz von Holzhausen sat down for a rare interview with CNBC this week at the Petersen Automotive Museum, detailing the Cybertruck's design process and teasing a new model he can't discuss yet. In fact, that's exactly what von Holzhausen has said about the new model.

When asked what his favorite design from his tenure at Tesla was, the chief designer said it has to be "the one that's coming," which he "can't talk about" yet. However, he did have much more to say about the Cybertruck, which Musk insists is coming next year.

Much of the truck's design was influenced by its medium-stainless steel. "The Cybertruck is one of these rare moments where in a way, form followed function. A lot of times we put the form in front of the function. Especially in the automotive world. And it's really tough to mix the two, but Cybertruck is really born out of the idea of a different way of manufacturing, a material that puts toughness on the outside," says von Holzhausen.

He continues, saying "So we really wanted to use stainless steel as a material so that the hardest part of the vehicle was on the outside, not the delicate paint. And it felt right for a truck that's used like a Swiss army knife in any kind of environment has to be tough."

From the sound of it, getting the design right proved difficult for a myriad of reasons, and may have contributed to the truck's somewhat liberal release timeline. "So stainless steel is really tough to form, especially when you make it bulletproof or thicker to withstand impacts and not be damaged. And so we really looked at new ways of manufacturing." Von Holzhausen says the medium limits a lot of traditional design avenues, too.

"You could only break form and form it in one direction. You can't do compound curves or things with the thickness of the stainless steel that we're using. So it really led us to a design that was really planar, really simplistic, and it was also a chance to break the paradigm of what pickup trucks have been for the past 60 or 70 years."