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HOW TO SCAN A CAR WITH LASER 3D SCANNER - Fiat Panda 3D scanning with photogrammetry

Updated: Nov 27, 2020

When the first generation of Fiat Pandas was introduced to the market at the March 1980 Geneva Motor Show, it was an unimpressive three-door hatchback designed by Giorgetto Giugiaro and Aldo Mantovani of Italdesign. But this model, which was assembled in Turin in Italy, quickly become a legend not just among the Italian people but in all of Europe. The main reason was that the Panda was designed as an inexpensive, easily maintained, utilitarian and robustly simple car. The second generation Panda, codenamed Model 169 and produced in a Polish Fiat factory, debuted in 2003, with almost no direct engineering linkage to the first generation.


When the first "Italian" Panda was produced, it was 3,3 m long and 1,4 m wide. The second edition is a slightly bigger car (3,5 m; 1,5 m) but we still consider it a small compact car for daily city rides. Its size makes the car a perfect "sample" model to test all the features of handheld laser 3D scanner and we were curious about the time we would need to get a complete model from start to finish. One of the unique features of ScanTech KSCAN Magic is the photogrammetry system implemented into the 3D scanner itself. Here is the workflow used for this project:


  1. Reference points, scalebars and scanning markers placement

  2. Photogrammetry shooting with KSCAN Magic

  3. Preparation of the surface with matting spray

  4. Scanning with KSCAN Magic

  5. Postprocessing of the data in scanning software




1. Reference points, scalebars and scanning markers placement

Using the laser handheld 3D scanner requires first placing the industrial markers. These markers are actually small removable stickers with reflective surfaces, which are shipped with each unit of the 3D scanner . There are two different sizes in each package: 3 mm and 6 mm. We decided to use the larger diameter and placed markers at the recommended distance of about 10 cm from each other. An important benefit of KSCAN Magic is the implemeted photogrammetry system which helps to ensure stable accuracy on large parts. The package of SCANTECH KSCAN Magic contains the scanning markers and also photogrammetry reference points (see the picture) which are necessary to place on the target. Reference points are magnetic, so you can remove them when the scanning is done and use them again next time.


Time needed: 60 minutes


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2. Photogrammetry shooting with KSCAN Magic Creating a network of reference points before scanning itself with a photogrammetry technology is highly recommended when scanning large or complex objects. This step will prepare a pattern of reference points on the surface of the object and will help ensure stable accuracy for the whole scanned object. The process is very easy - you place coded markers and scale bars on the object you plan to scan and, using KSCAN Magic, capture "photos" with the markers from various directions. After capturing enough of these images, the data will be processed by ScanTech photogrammetry software, which automatically calculates the 3D coordinates of all targeted points. The calculation is based on the principle of spatial image triangulation (photogrammetry) and is fully automated. The entire photogrammetry process is simple and doesn't require any special experience. Finally, the resulting 3D coordinates are transferred to the ScanTech scanning software and scanning can start directly following the prepared pattern.


Time needed: 30 minutes


3. Preparation of the surface with matting spray


Even though the laser scanning technology can practically do magic, there is still one limitation: a transparent surface. Due to the physical nature of technology, laser beams can't be captured on glass or similar surfaces. If you plan to scan a car, you will find some glass for sure. Fortunately, there is an easy solution - matting spray, which you can apply on the glass surfaces (in our case car front, side and back windows plus headlights and backlights). it is easily removed by washing, but for parts which are not washable from some reason, there is a disappearing spray, which will evaporate within one hour.


Time needed: 15 minutes


4. Scanning with KSCAN Magic


Laser scanning itself is simple job. The only thing you need to control is the distance bar on the screen of your laptop which tells you if you are in the correct scanning distance from the target. What is important during scanning is to keep the scanner perpendicular to the surface for the best data quality and low noise. It's also important that the scanner is able to capture (see) at least 4 markers at any time. It is also good to frequently change scanning angles and positions of the scanner to capture data from different directions.


Time needed: 60 minutes




5. Postprocessing of the data in scanning software


When you have captured all of the data, it's time to finalize your job in the scanning software. You will probably need to clean the background or surface. When you are done, you can use any of a variety of exporting functions such as holes filling, mesh simplification etc. and save your data to the STL file. Scanning software contains many automatic, semi-automatic and manual functions to work with scanned data, so you have many options. One of our favourite features is 3D comparison which allows you to compare your scanned data with the original CAD model. Our final file has 310 MB which is perfectly good for a small car.


Time needed: 15 minutes


Summary


The goal of this trial was to measure the difficulty of scanning a small car with a laser handheld 3D scanner with photogrammetry under specific outside conditions (especialy warm temperature and direct sun), as well as the time needed for whole project and all necessary steps, from unpacking the 3D scanner to exporting the final STL file. All of this with an additional element of a new user. The result is clear - all the steps are very intuitive and after an initial 60 minutes training, even a 3D scanning novice can perform useful results. We mus mention that to get a complete model of the car, it would be necessary to lift the car to scan the chassis and tyres but our test focused on the car body only.


Time needed: 3 hours

Technology used: ScanTech KSCAN Magic, DELL Precision 7540 laptop

Location: Brno, Czech Republic Outside temperature: 34 °C


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