3D scanners capture raw 3D measurement data in the form of point cloud or polygon mesh. Post-processing is the modeling stage where you clean up and transform the 3D scans into useable form.
There are 3D scanners in the market that have post-processing capabilities inside their 3D scanning software that satisfies basic applications such as 3D visualization. Additional advanced post-processing software may be required for other industry applications including reverse engineering and quality inspection.
3D Scanning Workflow
Data collection phase where several scans are captured from all sides of the part using a 3D scanner.
Modeling phase includes hole-filling, cleaning, aligning and merging individual scans into a digital 3D model.
Export for Use
Export the data into standard file formats (PLY, OBJ, STL, ASC, FBX) for use in downstream applications.
It’s important to realize you should always try your best to capture the best quality raw scans you can get during the data acquisition stage because scan quality only goes down after post-processing. No amount of post-processing work can ever save you from poorly scanned data.
Accuracy of scan data deteriorates
when it goes through too much post-processing.
You need fresh ingredients to cook an amazing dish. The same principle applies to 3D scanning. If you collect quality raw scans during the scanning process, you will have the best data to work with during the post-processing phase, which ultimately affects the final results.
Your output is only as good as your input.
The less processing work you do to the scan data means you get quality close to the original scan results. In addition, having quality scan data ensures you don’t need to spend too much time during the post-processing phase, saving you time and headaches down the road.
So, what can we do to ensure we get quality scans prior to post-processing?
Laying the Groundwork
Each 3D scanning job requires planning and preparation to ensure you capture the best quality scans you can get from your 3D scanner. It can also make a difficult project much easier to deal with. The objective is always to do it once well, instead of working in a perpetual cycle of rescanning the object over and over again due to poor planning. If the scan data you are capturing from your 3D scanner is noisy, it is often an indication that you need to improve on your scanner settings or the physical setup.
Planning and preparation = Less work later
Here are some tips to help you capture quality scans from the start:
If you have the space, it’s best to have a dedicated room for 3D scanning. A controlled environment minimizes movement and provides consistent lighting. While the 3D scanner is acquiring data, movement from either the scan object or the scanner creates noisy scans and inaccurate results. Make sure you are scanning in an area free from vibration from the ground (scanner placement) or surface such as a table (object placement). Having consistent lighting is important for scanning. Bright lighting also causes noisy data. It would be best to switch the lights off or dim the lights for better scanning results.
Depending on the scanner, typically scanning outdoors is not recommended due to the brightness of the sun. But if you must scan outdoors, make sure you are scanning in a shaded area away from direct sunlight with consistent lighting.
Use Proper Fixture
You don’t want the object to fall down half way through the scanning process due to improper mounting of the part. Make sure the object is placed on a stable surface. For objects that don’t sit well on the flat surfaces, you can use dark putty or clay to hold the part in place.
Scanning Challenging Surfaces
For laser and structured-light 3D scanners, it’s challenging to scan parts with shiny, dark, or clear surfaces because they use light as a projection source. Light scatters when scanning these difficult surfaces such as metal or glass. To overcome this challenge, a developer aerosol spray is handy to temporarily coat parts for scanning. It sprays a white powdery substance to create a matte surface finish. The white powder can be wiped off easily after scanning. In our 3D scanning lab, we use Magaflux Spotcheck® SKD-S2 developer spray. You can view our tutorial videos to learn more about how to prepare difficult surfaces for scanning.
Calibrating your 3D Scanner for Accuracy
Poor calibration produces inaccurate scan data. The calibration process helps the optical measurement instrument to determine its distance–its position, rotation, and behavior–relative to the scan object in order to capture accurate 3D scans. Some scanners require system calibration by the user while others are factory calibrated. The better the scanner is calibrated, the better scan data quality you will get. If you have to calibrate the scanner yourself, make sure you carry out the procedures very carefully. You can always contact your vendor if you have any questions on how to get the most accurate scan results from the calibration process.
Spinning the Object for Scanning
The data acquisition process requires that you capture multiple scans of an object from all sides for coverage. To help rotate the object with ease to get better quality scans, our team uses a motorized rotary table that automatically spins the object while scanning (photo on left). An inexpensive solution for spinning the object manually is to use turntable such as a Lazy Susan (photo on right).
Scan with a Dark Background
The scanner can pick up data from backgrounds (e.g. table) you don’t want while scanning. Eliminate noisy data by scanning on a black background. This makes sure the scanner only captures measurement data from the object you are scanning. You can use black paper/foam board from the craft store or a black cloth from the fabric store to cover surrounding areas such as the scanning surface upon which you place your object or the wall.
Use the Correct Scanner Settings for the Part
One of the culprits of getting bad scans is the result of using incorrect scanner settings when scanning the part. For example, in order to capture good scans from the HDI 3D Scanner, the scanner’s exposure and brightness settings need to be adjusted according to how light or dark the scan part is (View video demonstration). Make sure you use the proper settings to get optimal scan results from your scanner.
Easy to overlook, but the user’s skill level is one of the most highly controllable factors that impacts scan quality captured by the scanner. Even if you have the best equipment, without proper training, you won’t be able to extract the most potential out of the equipment. Because your 3D scanning vendor uses the equipment on a regular basis they can provide you with the expertise and tips on how to use the 3D scanner to its maximum potential. If you have more time, getting training from a professional is strongly recommended. If you prefer to learn on your own, you can inquire about getting online training through manuals, videos, and guides. It’s important to take time for training before starting the project.
Quality of the 3D Scanner
The ability to getting good scans will improve with practice and experience. You can learn a lot from mistakes, which will train you to become a 3D scanning expert.
It’s also important to remember that aside from preparation, the quality of the scanner will affect the quality of the scan data it produces. For example, professional 3D scanners using high quality components will produce better scan data quality compared to consumer-grade scanners. To learn more about this topic, please read our previous blog post related on how different types of 3D scanners affect scan quality.
Lovely, guys! Enjoyed the reading, its all valid and so true. Now a survey of the available systems would be good! Only there is about 100 companies by now…
Thanks for your feedback Gerd! It would be an ambitious project to review all the 3D scanning systems available in the market. However, we are looking to write a resource on different types of measurement tools for comparison, so please stay tuned.
Always reflect what an amazing job GoMeasure3D did when helping me to scan parts for a project. Absolutely wonderful people to work with !
Lyman, thanks for your kind words. We really appreciate that you came to us for your 3D scanning project and we’re happy to help you out whenever we can.
Great article. After reading this I was hoping you might be able to answer a question for me? What is the difference in scanning at say 250 dpi in the initial scan VS scanning at say 50 dpi and increasing the resolution to 250 post scan?
Thanks for commenting! Regarding your question, it’s better to scan at 250 dpi, as opposed to increasing the resolution from 50 to 250 post-scan. This is because you will be able to pick up the fine details from the physical model in the initial scan instead of assuming that there is no small difference in the part along that area. For instance, for a flat plane there wouldn’t be a big difference if you scan at 250 dpi or 50 dpi, but for a tight curve of a part or a small feature (like a chamfer or sharp edge) you would gain much better clarity to the actual positioning of the feature at a higher resolution of 250 dpi.
If you can, it’s always better to get the best quality scan data you can because scan quality only goes down after post-processing. You can’t get better quality data than you originally capture.
I hope that answers your question. If you have further questions. Please feel free to contact us.
For quality scanning we should use quality scanner to get premium touch as the object should be in proper position scan with dark background always use the correct scanner setting for avoiding bad scans.