In today’s digital age, almost no engineers work on drawing boards. Instead, all design and industrial-production works are performed in CAD software.
Computer 3D modeling not only allows you to see an object from different angles, but also makes it easy to identify possible weaknesses in design.
Today, designers have access to large libraries of 3D objects available in different formats, such as STL, PLY, OBJ, MAX and others. However, what if you need to create a 3D model from a physical object you have? To do this, you’ll need a a 3D scanner that meets your specifications.
3D Scanning Methods
Modern 3D scanners can be grouped based on their scanning methods. The methods are:
Contact
Contactless
a) Active Scanners
These scanners illuminate an object with light of a certain wavelength or a laser. After the illumination, the scanners catch the reflection and build a geometric map of the object based on it.
b) Passive Scanners
These 3D scanners do not emit anything. Instead, they rely on the light of the visible spectrum reflected by the object.
Now that we know the main classifications of 3D scanners, let’s find out how you can choose the right one for 3D printing
Choosing a 3D Scanner for 3D Printing
To find the right 3D scanner, ask yourself the following questions:
1. What size objects do you intend to scan?
The size of the object you will be scanning will determines the field of view your 3D scanner should have.
Scanning Large Size Objects
If you are planning to digitize cars, architectural elements of buildings and other large objects , you will need a scanner with a wide field of view. There are only a handful of companies that produces such devices. For example, Leica and Faro produce professional grade 3D scanners in the $30,000 to $100,000 price range.
If you need a more affordable device, look for 3D scanners from Matterport. They are somewhat inferior to the elite class equipment in terms of functionality. However, they are easy to assemble and use.
Scanning Medium Size Objects
If your goal is to digitize medium-sized objects (from 0.3 to 5 meters), you’ll want to use 3D laser scanner. These devices can either be mounted on a tripod or be handheld.
3D scanners mounted on tripods are more accurate. However, the handheld ones are more mobile and, therefore, they scan faster.
3D laser scanners are the most popular on the market. Therefore, their characteristics, functionality and costs vary greatly.
The leading manufacturers of 3D laser scanners include RangeVision, 3D Systems and Creaform. Thor3D, which released the world’s first wireless 3D scanner in 2015, is also one of the companies with great 3D laser scanners.
Scanning Minute Objects
If you intend to scan microscopic objects or individual highly detailed areas of objects, you will need a 3D scanner with a 3D microscope function. The best of these scanners are manufactured by the Japanese company Keyence.
These high-precision 3D scanners are used in highly specialized fields. They are often purchased as add-ons to dental 3D printers or jewelry 3D printers.
If even greater precision is needed, then Nikon CMDs will come to the rescue. The equipment of this Japanese giant will allow you to create 3D models with an accuracy unattainable with any other device. However, these devices are quite expensive. Typical price price starts from $100,000.
2. Do you need to capture the texture of an object?
Before you buy a 3D scanner, consider whether you’ll need to capture the texture of an object. Most modern scanners are not capable of this. For those that can capture texture, the functionality is mainly a secondary addition while the priority is to get an accurate geometrical map of the object.
If it is important to accurately convey the texture of an object (for example, when creating a 3D copy of a museum exhibit), find out the resolution that the 3D scanner captures it. Also, check examples of objects that the 3D scanner has scanned.
If capturing texture of an object is not important choose a budgetary version of the scanner and focus solely on the accuracy of determining geometric vertices.
3. Do you need high resolution?
With 3D scanners, “resolution” refers to the minimum gap between the irregularities of the scanned object. For example, if there are two protuberances or depressions on a plane, then the resolution specified in the characteristics of the 3D scanner will indicate the minimum gap at which these geometric elements will not merge and will be visible in the final 3D model.
Generally, resolution is indicated by the manufacturer in millimeters or microns. The lower the value, the higher the resolution of the scanner and the more small details it will be able to bring out in the built 3D model.
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Resolution is one of the most important features that you need to pay attention to when choosing a 3D scanner.
Let’s look at it in more detail.
At first glance, you may think that high resolution is better and that you should always set the maximum value in the scan settings. However, this is not quite true.
In practice, people purchase high-resolution 3D scanners. However, most of the time, they leave this figure at average values when scanning.
A higher resolution requires more computing power since when working with CAD, the computer will have to process several times more geometric vertices. The same applies when printing a scanned figure on a 3D printer. Due to the more complex geometry, the procedure will take much longer.
At high resolution, the file size is also big. So, for example, at a resolution of 0.7 mm, a 3D model of a small sculpture (60 cm in height) was 156 Mb. At a resolution of 0.5 mm, the model file size was 308 Mb. An increase in resolution of just 0.2 mm resulted in an almost two-fold increase in file size.
In our subjective opinion, if there is no clear need for high detail, there is no point in overpaying for a high-resolution 3D scanner.
To make it easier for you to choose a 3D scanner, here are the recommended resolution settings for various objects:
- Jewelry: 0.08 – 0.35mm
- Lips, eyes, ears: 0.2 – 0.5 mm
- Face: 0.5 – 0.8mm
- Full height adult: 1.6 – 3 mm
- Passenger car: 2.5 – 4 mm
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There are many examples when high resolution is not necessary. In fact, configuring it upwards in settings will only slow down the process of scanning, processing the model and subsequent printing on a 3D printer.
For example, let’s say you want to make a full-length human figurine 30 cm in size.
For this task, you do not need a high-resolution 3D scanner since on the final product you will hardly be able to see wrinkles, moles or any other small features. Why then overload the equipment with unnecessary data? A resolution of 2 – 2.5 mm will be quite sufficient.
Also, let’s say you want to scan large objects with simple geometry (for example, furniture). When creating a 3D model of such objects, it is important to correctly convey their shape, and not to reveal all the roughness, chips or cracks.
To avoid damage to the retina, it is not recommended to use 3D laser scanners to scan faces.
4. What equipment do you already have?
When choosing a 3D scanner, think of the equipment you already have. There is no need to purchase a high resolution 3D scanner if the 3D printer you have cannot reproduce all the details of the scanned object.
Moreover, the processing power of the workstation you have is also important. It can take more than a day to process a truck model scanned with a resolution of 0.4 mm, even for a top-end computer with an i7 6900K processor and an Nvidia QUADRO P5000 video card.
Moreover, you will not be insured against buffer overflows and other errors. Should such errors occur, the whole procedure will have to be restarted.
Summary
There are many devices for a wide variety of tasks for 3D scanning. When you have the right 3D scanner, you can easily reverse engineer any object.
Virtual museums are being created today with the help of 3D scanners. In game development, 3D scanners are used to digitize actors’ faces. Also, American forensic experts not only take photographs, but also scan crime scenes to create detailed 3D models.
To find the right 3D scanner for you, it’s important to know the tasks that you want to solve. Answering the questions above will significantly narrow your search to the right device.
