Since 3D scanners have become more affordable, 3D scanning has changed the world of custom 3D printing. In the past, 3D scanning was only used in the production of military equipment and spacecraft parts. With desktop and portable 3D printers available for a few hundred dollars, 3D scanning has found a place in fun and hobby projects at home. You can take your 3D printing projects to the next level with an affordable 3D scanner. After all, custom 3D printing is a hot new phenomenon. Even minimal 3D scanning is available on smartphones like the iPhone 12 Pro and iPhone 13 Pro. This article will discuss 3D scanning, what it is about, and how to get started with 3D scanning.
What are 3D scanners?
3D scanning converts physical objects into 3D digital models, capturing the object's shape and geometry. It is a non-destructive, non-contact technology that creates data point clouds from the surface of an object with the help of laser scanning or other scanning methods. It helps to acquire the exact shape and size of a real object as a 3D digital representation. 3D scanning also helps capture details of complex geometries and irregular contours, which are impractical to measure, model or estimate with traditional methods.
3D Scanners for Back Engineering
3D scanning is not something new. It has been used in the military, aircraft and aerospace industries for reverse or reverse engineering. Reverse engineering is a process of recreating a product or part without documentation, drawings or 3D models. 3D scanners have been used to create digital CAD models for parts that need reverse engineering or reengineering. 3D scanning has been useful in regeneration, optimization and modification of parts. Reverse engineering involves three steps. The first is to acquire a 3D representation of an object with the help of a 3D scanner. Second, the captured 3D data is converted into a solid 3D model using specialized software. Finally, the model is processed to eliminate artifacts and refined to make it ready for production. It is later converted to a suitable format, which can be 3D printed.
As 3D printing has become increasingly popular, 3D scanning has been reinvented to make it more accessible for custom 3D printing. With 3D scanners worth a few hundred dollars, 3D scanning has reached everyday users, who can utilize the technology to tweak and enhance their regular 3D printing projects. For intermediate to advanced 3D printing users, a 3D scanner is a must-have piece of equipment.
How do 3D scanners work?
Firstly, 3D scanners collect data with the help of laser scanning. The object to be scanned in 3D is placed on a table that serves as a spatial reference for the scanner. Using specialized software, the scanner probe moves around the object, capturing the details of the object's surface. The probe projects a laser beam onto the object's surface, which is recaptured by two camera sensors. The camera's sensors track changes in the distance and shape of the reflected laser beam along three dimensions as the probe moves around the object.
The result of a 3D scan is a collection of millions of points called a Cloud . The point cloud is a raw 3D representation of the object's shape. A 3D scanner typically captures up to 750,000 points per second with a high accuracy of about +/- 0.0005 percent.
The point cloud is stored as a computer file. The file is then merged and processed with the help of specialized software to create a digital CAD model. Sometimes the created CAD model can be compared with a user-designed 3D model to provide a color map deviation report. The report is a PDF detailing the differences between the scanned and expected CAD models.
Finally, the scanned model is processed and refined to generate a surface model or a solid 3D model depending on the application. Post-scan processing of the scanned model is usually the subject of the specific use case. There are many different types of 3D scanners based on their technology. Regardless of the scanning technology, 3D scanners work the same.
3D scanning applications
3D scanners are no longer restricted to spacecraft or military production. 3D scanning is now a widely used technology across multiple industries, including home entertainment and hobby projects. Some of the notable applications of 3D scanners are below.
3D Printing for Hobbyists : Handheld and desktop 3D scanners are useful in recreating household items, repairs, miniatures, toys, and other hobby projects.
Dental : 3D scanning is used to design custom crowns and bespoke implants to meet the specific needs of dental patients.
Medical : 3D scanning is used in a variety of medical applications, including orthopedics, plastic surgery, and prosthetics. Digitalization is also used to design mobility aids and wheelchair accessories. It is now also used to create realistic mannequins for medical practice.
Jewelry : 3D scanning is often used for replicating, duplicating, and repairing antique jewelry. It is also used to digitally store discontinued jewelry designs or modify and improve current designs.
Architecture : 3D scanning is widely used to scan buildings for repairs, surveys and modeling.
Archeology : 3D scanning is used to digitally conserve historical objects, artifacts, skeletal remains, and even archaeological sites.
forensics : In forensic science, 3D scanning is used to replicate crime scenes and evidence like footprints, murder weapons, bullet holes, blood stains, etc.
Reverse engineering : 3D scanning has been widely used for reverse engineering and reengineering in areas such as automotive, aerospace and military technology.
3D scanning technologies
3D scanners are often classified based on scanning technology or method. The broad classes of 3D scanners are below.
Laser triangulation : This is the most commonly used 3D scanning technology. In these scanners, a laser beam is projected from a probe onto the surface of the object and reflected by a laser sensor that captures laser lines. Based on the reflection angle of the laser sensor, the scanner captures precise and precise details of the object's surface and texture using various trigonometric functions. However, the laser triangulation method is useless if the object is transparent or has shiny surfaces.
Structured Light Scanning : This is the most effective method of 3D scanning and is used by handheld 3D scanners. In this method, a pattern of light is projected toward the object and a pair of camera sensors capture the reflected light. Camera sensors are placed on both sides of the projector. These camera sensors measure light patterns from each side and calculate differences at each point in a given field of view. The sensors evaluate how the object warped the light pattern by triangulating multiple reference points across different object scans. By repetitive triangulation and comparison, the exact shape and dimensions of the object are derived with the help of specialized software. This 3D scanning method is more effective and portable. However, scanning may be affected by lighting conditions. Therefore, it is often used for specific 3D scanning applications such as medical, dental, and archaeological.
3D LiDAR Scanning : This type of 3D scanning is used by smartphones like the iPhone. In this method, beams of light are projected towards the object and then the shape and dimensions of the object are calculated based on the time it takes the light to reflect. The working of LiDAR scanners is identical to time-of-flight scanners used to map terrain, buildings, and architectural structures.
Laser pulse scanning : This is also called time-of-flight scanning. In this type of 3D scanning, laser pulses are fired at an object and captured by a sensor. Based on the time interval between the emission and collection of pulses, the geometric details of the object's surface are calculated.
Photogrammetric scanning : In this type of 3D scanning, a 3D model of an object is constructed with the help of a collection of 2D photographs of the object. The method uses computer vision and geometric algorithms to create a 3D representation of the surface or object.
Contact-based 3D scanning : In this method, points on the surface of an object are captured using a mechanical or physical probe.
Types of 3D Scanners
In addition to 3D scanning technology, 3D scanners come in various sizes and models. A 3D scanner for scanning jewelry would not be useful for scanning large objects. Likewise, a flatbed 3D scanner would not be used for architectural surveys. 3D scanners are generally identified by their application. The main types of 3D scanners are as follows.
- Desktop 3D scanners
- Portable 3D scanners
- 3D scanners for jewelry
- Terrestrial LiDAR Scanners
- 3D metrological scanners
- Simultaneous localization and mapping (SLAM) scanners
- Dental desktop 3D scanners
- 3D body scanners
How to buy a 3D scanner
Many important considerations must be made before opting for a specific 3D scanner. First, you need to select 3D scanners based on your use case. Each type of 3D scanner is generally only suitable for a specific application. For example, for custom 3D printing, a desktop or handheld 3D scanner would be required. Contrary to this, a SLAM or iMMS scanner would be required for architectural scanning. A specific use case may restrict the available 3D scanner options, as many applications can only be served by industrial 3D scanners.
You may also need to consider the size of the objects to be scanned. For small objects, stationary 3D scanners are better as they provide greater resolution and accuracy. Portable scanners are suitable for large objects that need to be scanned outdoors. Handheld scanners may not have the resolution, speed, and accuracy that stationary scanners offer.
Before taking into account the main features of the available models, the next consideration is budget. Professional 3D scanners are available from a few hundred dollars to tens of thousands. The price ranges from $400 to $200,000 for 3D scanning equipment. For the most common uses, we can divide 3D scanners into three price segments: budget 3D scanners (price up to $1,000), professional 3D scanners (price between $1,000 and $10,000) and industrial 3D scanners (price above of US$10,000).
The next important factor when purchasing 3D scanners is speed. It depends on whether the scanner was purchased for professional, industrial or personal use. Ideally, a 3D scanner should be fast, with a scanning speed of millions of points per second and at least 20 FPS. For personal or hobby use, speed may be compromised.
Another critical factor is resolution and accuracy. The accuracy of a 3D scanner is usually specified in mm. Cost-effective 3D scanners provide an accuracy of 0.1~0.2mm. Industrial 3D scanners are capable of providing accuracy down to 0.009 mm. The greater the precision; more detailed 3D models can be built.
Finally, software support from a 3D scanner should also be considered. The software capabilities of a 3D scanner can range from basic 3D scanning to high-level post-processing of 3D models. One more critical factor when choosing a 3D scanner is its connectivity. Most desktop 3D scanners use a USB interface to connect to a computer. Professional flatbed scanners can also provide connectivity through Bluetooth and WiFi. Portable 3D scanners are often designed to be paired with power banks and smartphones.
Top 3D Scanners
Desktop and handheld 3D scanners are available in all price segments. Some of the budget 3D scanners in 2021 include Revopoint POP, Creality CR-Scan 01, Phiz 3D scanner, Matter and Form V2 3D scanner, Structure Sensor Pro, BQ Ciclop, Shining 3D EinScan SE, Artec EVA, Scan Dimension SOL, Shining 3D EinScan SP, iPhone 12/13 Pro, Scantech KSCAN, Shining 3D EinScan Pro 2X Plus, Zeiss T-Scan Hawk, Creaform Goscan Spark, Evatronix EviXscan 3D Quadro+, Zeiss GOM Scan 1, Artec Space Spider, Artec Leo 2022, Faro Freestyle 2 , Creaform Academia 20, Polyga Compact S1, Creaform Handyscan 307 Silver, Peel 3D 1, Peel 3D 2, Peel 3D 2S, Artec Eva and Evatronix EviXscan Optima+ M. Some of the professional 3D scanners in 2021 include Shining 3D EinScan H, Shining 3D EinScan HX, Scantech iReal 2E, Scantech SIMSCAN, Creaform Handyscan Black Elite, GOM Scan 1 and GOM ATOS Q.