How did Cadillac’s gorgeous Elmiraj concept go from clay to a digital model, and back again? The answer is structured-light 3D scanning — an advanced measuring technology. Often used for fine art restoration and reproduction, the technology helped in the creation in the masterpiece that is the Elmiraj concept car, as its designers used the digital mapping technique extensively.
According to General motors, 3D scanning “uses projected light patterns and an advanced camera to capture three-dimensional shapes and translate them into math data that can be manipulated in digital modeling programs.” As the light pattern is projected onto the vehicle’s surface, a camera looks for distortions that represent curves or contours, recording where the object is in space and its orientation. Each scan is then digitally stitched together until the complete vehicle is captured. The data can then be uploaded into a computer-controlled milling machine to create a full-scale model, and a portion of the vehicle can be transferred to a 3D fabricator for a rapid prototype part.
“With the Elmiraj, we were able to use 3D scanning as the bridge between traditional hand-sculpting teams who work in clay and digital modeling design teams who work in math,” said Frank Saucedo, director of General Motors’ North Hollywood Advanced Design Studio. “Our ability to scan the clay model with speed and precision and go from the digital tools to the hands of a craftsman and vice versa was extremely valuable.”
3D scanning also plays a significant role in car design, which typically begins when a 2D image is converted into a 3D mathematical rendering. “Math models serve as the basis for computer-controlled milling and hand-modeling in clay”, while “3D scanners allow designers to quickly reverse-engineer and update the master math model”, according to a GM news release. Changes made to the math model are then updated in the physical model by milling the clay.
General Motors has been using 3D scanning since 2001, stating that it has applied the technique primarily to clay interior and exterior properties rather than drivable concepts, the Elmiraj concept being an exception. During each phase of the vehicle’s build process, The General’s Design Center Fabrication Shops in Warren, Michigan and Advanced Design Studio in California used 3D scanning to validate nearly every pattern, mold, and part.
Another advantage of 3D scanning is that it enables designers the opportunity to go back to an earlier version of the design.
“It provides a means of recording every design change with the utmost accuracy,” said David Bolognino, director of GM Design Fabrication Operations. “A scan can even reveal the need to take a step back to a previous iteration, and 3D scanning makes it relatively easy to do.”
GM performs tens of thousands of 3D scans every year. It also uses laser-based and structured white and blue light scanning in engineering applications, competitive benchmarking, and in assembly plants for trouble-shooting part irregularities.
“Thanks in part to 3D scanning, we can translate surface from a scale model to a full-size model in less than one week now,” said Bill Mattana, senior manager of global surface creation at GM’s Warren Design Center. “Not only is Elmiraj a stunningly beautiful concept car, it served as a tremendous opportunity for extending our use of 3D scanning.”
The GM Authority Take
3D scanning lives at the intersection of creative design and math, and it is absolutely wonderful to see GM living on the edge of high-tech vehicle design.