what is 3d scanning guide

What is 3D Scanning? – Definition, Advantages and Uses

3D scanning involves collecting data about the shape and appearance of a physical object, structure, environment or person and then using that data to construct digital 3D models. 3D scanners are used to analyze objects and environments, collect the data and construct the model.

3D scanning is used across a wide range of industries, from architecture and engineering to medicine and entertainment. By allowing workers in these industries to examine objects digitally,

3D scanning can help make their work more accurate and efficient. 3D scanning is also compatible with 3D printing and CAD (computer-aided design), and it can even be used for reverse engineering.

That’s a very basic explanation of 3D scanning, but there’s a lot more to learn about this important process. This guide covers everything you need to know about 3D scanning, including the different techniques, advantages, limitations, applications and how 3D scanning works.

What is 3D Scanning? The Basics

While there are a variety of different 3D scanning techniques, they all rely on the same principles. All 3D scanners use a sensor, which may be a physical probe, laser or light, to measure the distance between a camera and an object.

3D scanners are able to identify 3D points, calculated from photos and depth measurement using triangulation, with each point appearing on the screen individually. Altogether, these 3D points form a point cloud, which appear like in the image below. The process of extrapolating the shape of a subject from points is known as reconstruction.

3D scanning point cloud

Once the scanner has created the point cloud, it then meshes it to turn it into a 3D model made up of surfaces. Meshing essentially means you are connecting the dots of the point cloud to produce a complete model. A mesh is a collection of vertices and faces, along with information of how the vertices make up the faces. Rather than valuing each point equally during the meshing process, you can deprioritize some of the points to create a mesh that isn’t extremely complex and therefore is easier to work with.

Finally, the mesh is textured. In the context of 3D scanning, texture refers to an image painted upon a service, and applying a texture to a surface is called texture mapping or UV mapping. Textured images are stored in a special file where every pixel with U and V coordinates has a corresponding color. Many 3D scanners have a special camera for capturing texture that allows them to collect color information at each point. Bright and uniform lighting is required for optimal results, unless the scanner is equipped with a flash.

3D scanned person

Generally, several scans are required in order to create a complete model, as the scanner needs to collect information from every side of the subject. Scans are brought together into a common reference system, a process known as alignment or registration. The scans are then merged to create a 3D model. The whole 3D scanning process is known as the 3D scanning pipeline.

3D Scanning Techniques & Advantages

There are a wide variety of different 3D scanning methods, each with its own advantages and disadvantages. Here’s a look at the main 3D scanning techniques.

Contact-based 3D Scanning

As the name suggests, with this technique a scanner collects data on an object through physical touch. The object either rests on a surface plate or is held in place by a fixture as it is probed by the scanner, and the software used with the probe will detect how and where the probe touches the object’s surface and record the 3D location of the surface. A coordinate measuring machine (CCM) is an example of a contact-based 3D scanner.

Contact-based 3D scanning is often used in manufacturing, particularly for performing quality control of parts during maintenance operations or after fabrication. This technique is very precise and can be used to 3D scan transparent or reflective surfaces, but on the downside, it is slower than most other 3D scanning techniques and isn’t well suited to scanning freeform shapes.

Contact-based 3D scanning

Laser Triangulation 3D Scanning

This type of 3D scanning uses either a single laser point or a laser line to scan an object. The laser is cast by the 3D scanner and reflects off the subject, modifying its initial trajectory. The change in trajectory is recorded by a sensor and allows the system to calculate the specific angle of deviation using trigonometric triangulation. With enough laser scans, the scanner can map the subject’s surface and create a 3D scan.

Laser triangulation is a highly accurate 3D scanning technique that produces high resolution scans. Its main limitation is that it isn’t ideal for scanning objects with transparent or shiny surfaces. Laser triangulation scanners are often used to probe the environment.

Structured Light 3D Scanning

Like laser triangulation scanners, structured light scanners also use trigonometric triangulation to create scans. However, rather than using a laser, this technique projects a series of linear patterns of light onto an object. Two sensing cameras analyze the light patterns, examining the length of each line to calculate the distance to the subject. The scanner can then calculate exact X-Y-Z coordinates to create extremely accurate 3D models.

As well as being highly precise, structured light 3D scanning is fast, produces high resolution scans, and is suitable for scanning people. On the downside, it is highly sensitive to lighting conditions, so it doesn’t work well outside.

Laser Pulse-based 3D Scanning

Also known as time-of-flight scanning, this method creates scans using the speed of light and sensors rather than triangulation. Laser pulse-based 3D scanners do this by measuring how long a casted laser takes to reach an object and come back via reflection. The laser and sensor hardware is rotated by a mirror, which allows the software to collect 360 degrees worth of data and capture the information needed to create a 3D model.

The main benefit of laser pule-based scanning is that it can be used to scan very large objects, structures and environments. It is, however, a slow method in comparison to other 3D scanning techniques.

Photogrammetry

Photogrammetry is a technique for obtaining measurements and other dimensional information of objects and environments from high resolution photographs. Photogrammetry can be done using aerial or handheld cameras which are used to take a series of overlapping photos of the subject. Photogrammetry software is then able to create 3D models by point matching the geometric intersection of light rays and using triangulation to decipher information like camera angles, locations and characteristics of the subject.

This technique is used across a range of industries and is particularly important in land surveying, engineering, agriculture and forestry. It has numerous advantages, including high accuracy, affordability and the ability to access difficult locations, but it’s also affected by the weather and environmental restrictions.

Photogrammetry

3D Scanning Applications

3D scanning is used across a huge range of industries, and as scanning and software capabilities continue to develop, it is becoming ever more important across various sectors. Here are the main applications of 3D scanning.

Entertainment

3D scanning is used to create 3D models in the movie, television and video game industries. In TV and film, it is often used in virtual cinematography, where it can be used to quickly scan real-world objects Artists commonly sculpt physical models and then 3D scan them, rather than manually create digital models with 3D modeling software.

3D scanning plays a similar role in the gaming industry, where it’s used in the creation of characters, props and landscapes, but it is also used in the development of virtual reality gaming. It can be used to create lifelike 3D representations of objects, people and spaces, so it’s very useful for creating immersive and interactive virtual gaming environments.

Medicine

3D scanning is becoming increasingly important in the medical world. One of the main benefits is that it can be used in the creation and customization of prosthetics, implants and wearable devices such as casts and braces. For example, prosthetics can be designed with great accuracy, increasing patient comfort, and 3D printing means they can be produced quicker and cheaper than traditional methods. 3D scanning is particularly common in dentistry for creating dental implants and other objects.

Another notable use of 3D scanning in medicine is 3D ultrasound, where the technique can be use to create 3D images in obstetrics.

Architecture

3D scanning can be used to scan and analyze entire buildings in precise detail, which is hugely beneficial to architects. Like in construction, the point clouds produced by 3D scanners can be used to highly accurate measurements and visualizations. Doing this via 3D scanning and CAD software is far cheaper and quicker than traditional methods. 3D scanning is also useful to architects for reverse engineering of aspects of buildings, from exteriors to internal future.

Construction & Engineering

3D scanning has a wide range of use in the construction and engineering fields. Aerospace was one of the first industries to use 3D scanning, but now it’s used in most construction, manufacturing and engineering processes. For example, in construction it’s useful for site modeling, the documentation of historical sites and quantity surveys, while in engineering it can be used to inspect equipment and for reverse engineering.

Reverse engineering is a particularly interesting use of 3D scanning. Parts produced several decades ago are generally only described via two-dimensional drawings, which can make accurate reproductions both difficult and time consuming. However, with 3D scanning, data of the shape of the object can be collected with great accuracy, and that data can then be used to create a new 3D model.

This model can then be used to create new molds and tooling, allowing manufacturers to create brand new parts with the same dimensional characteristics of the original. These reverse-engineered models can also be used to 3D print duplicates of the original. For example, 3D scanning can be used to restore classic car parts that aren’t available anymore. As 3D scanning removes much of the guesswork and is much faster than traditional reverse engineering, the process is extremely streamlined and results are highly accurate.

Archiving & Historical Analysis

3D scanning is increasingly popular among historians, art historians and archaeologists as a method of documentation and analysis. 3D scanning creates reproducible, highly accurate 3D models of artifacts and works of art, so it’s an important technique in archiving and curating. In addition, it allows for the sharing of accurate copies across the research and teaching communities.

3D modeling is also useful for historical analysis; for example, it’s often used in the modeling of facial features of humans’ evolutionary ancestors by scanning fossils. Other examples of the use of 3D scanning of historical artifacts include the scanning of sculptures by Michelangelo, the Kasubi Tombs in Uganda and Cuneiform tablets.

3D scanning artifacts

Design

Rapid prototyping and reverse engineering are very important to the design process of many products, so 3D scanning it a useful tool for many designers. When designers look to mimic natural materials, 3D scanning provides a fast, accurate way to study complicated arrangements and create new designs. In addition, 3D scanning provides great accuracy with complex parts and shapes, allows for shared web scans, and allows for coordinated product design using parts from various sources.

Forensics

3D scanning is now also a very important forensics tool for law enforcement officials. It’s valued for its ability to create highly accurate models of crime scenes, accidents, bullet trajectories and then bloodstain patterns. 3D scanning is useful for both documentation and analysis in this context.

3D scan forensics

3D Scanning Accessibility

If you’re interested in 3D scanning yourself, you’ll be glad to know that the technology is accessible to beginners, students and hobbyists, even if you’re on a tight budget. There are many small, handheld scanners suitable for home use which can be purchased for just a couple hundred dollars. Of course, the more you’re willing to pay, the higher quality scanner you’ll be able to get your hands on. The best 3D scanners, used by professionals, cost tens and even hundreds of thousands of dollars.

Conclusion

3D scanning is a technique for creating digital 3D models of objects, structures, environments, and even people. 3D scanners do this by collecting data about the shape and appearance of a subject, using calculations to construct a point mesh from the data, and then meshing and texturing to create a complete 3D model.

There are several different 3D scanning techniques, including contact and laser scanning methods, each with their own advantages and disadvantages. However, all 3D scanners are able to create highly accurate 3D models. The fact that they can often do this in a faster, cheaper way than traditional methods means 3D scanning is used across a wide range of industries, from entertainment and medicine to architecture and forensics.

3D scanning technology is constantly evolving and the last two decades have seen it becoming of increasing performance across a variety of sectors, and its importance is sure to increase even further in the coming years. There have even been strides made to incorporate laser scanning technology with smartphone apps, and it’s likely that someday we’ll be able to simply record videos on our phone and create 3D models from then, so the future is certainly bright for 3D scanning.