3D scanning of the car body using photogrammetry

How can I keep my accuracy up and save time when 3D scanning large objects? Take advantage of the support networks. Students of Moscow Polytechnic University know this and successfully apply it. Let’s look at how they digitized the car for virtual testing.

Students of the Faculty of Mechanical Engineering, specializing in Innovation, set the goal of their graduation project to improve the aerodynamic qualities of a racing car. To do this, they plan to solve several tasks. First, scanning and reverse engineering, then conducting virtual tests on a 3D model and refining the aerodynamics of one of the body elements, eventually designing and manufacturing this element. Such a consistent approach requires a sufficient amount of time. Therefore, we will first consider collecting information about the car body, and when the young specialists finish the project, we will ask them for a description of the remaining stages.

In order not to lose accuracy in stitching scans when digitizing a large object, photogrammetry technology was used. This is the collection of information about the location of reference points. Markers were glued to the body of the car: 5 mm uncoded (white with black dots) and coded (black with radial strokes). The coordinates of these markers were determined using the AICON photogrammetry system.

Next, the RangeVision Spectrum 3D scanner was calibrated to the first scanning zone, and the photogrammetry reference network was loaded into the ScanCenter NG program. The tags helped Spectrum navigate more accurately in space. This saved time by reducing the overlap density at the scan boundaries. If you don’t need a 3D model of the entire object, you can scan elements that are far apart without space between them. The support network clearly positions the parts relative to the whole. For example, the relative position of the front and rear bumpers will be preserved.

In addition, photogrammetry makes it easier to scan hard-to-reach elements. If you remove the spoiler from the car, fix it, avoiding changing the geometry, and digitize it separately, the system will map the element to the reference network using markers and virtually "put it back in place." Another life hack that has saved time is the double exposure mode. It is available in ScanCenter NG and is available for all RangeVision scanners. The black stickers on the white car would have to be digitized in two scans if it weren’t for him.

The work on creating a reference network and 3D scanning took one working day. Now we have to reverse engineer the body elements and simulate aerodynamic tests. We wish the students fruitful work and successful graduation.