3D scanning puts physical measurements into the computer world in an organized manner, resulting in digital 3-dimensional models. Whether sculpting a clay model or using a handheld laser scanner, the end result is the same—a digital representation of the object.
Laser-triangulation based scanners measure surfaces with point values that have x, y and z coordinates. These points are grouped into what is called a “point cloud” which is then meshed into surfaces.
Conceptualization
3D scanning is a digital technique that captures the shape of an object. There are several different types of 3D scanners, and they use different methods to collect data that can be used to create a digital model. Some are purely geometric, while others can also capture color. Regardless of the type of 3D scanner, they all translate the shapes of physical objects into digital models that can be used for all sorts of purposes.
One popular form of 3D scanning is photogrammetry, which uses photos to reconstruct a 3D model. This type of scanning can be used for all sorts of applications, from art to industrial manufacturing. Another form of 3D scanning is structured light scanning, which works by projecting a pattern of light onto an object and then measuring how the object distorts the light pattern. This type of scanning can be used to construct a digital model, and it is sometimes combined with photogrammetry to create an even more accurate model.
Other forms of 3D scanning are non-contact and can be used to capture the shape of an object without touching it. This type of scanning is often used for manufacturing and quality control applications, where the shape of an object must be accurately captured without damaging it. These types of scanners can be used to create a point cloud, which is a collection of points that represent the shape of an object. This can then be used to generate a CAD model of the object.
Several projects are using 3D scanning to record the condition of cultural heritage artifacts, which can then be used for educational and research purposes. For example, the Petrie Museum of Egyptian Archaeology has been using 3D scanning to create a digital library of Egyptian artifacts, and English Heritage has conducted a variety of projects to scan a wide range of historical objects and buildings.
The combination of 3D scanning and 3D printing can be used to replicate physical objects that cannot be reproduced otherwise. For example, a gargoyle from a church can be digitally acquired and then used to create a real resin replica of the original. This can be an easier and faster way to recreate a specific object than trying to build it from scratch with traditional modeling software or using the complicated process of plaster casting.
Reverse Engineering
The opposite of the forward engineering design process, reverse engineering is working backwards to understand how something was created. This includes dismantling products to analyze their inner workings, often for the purpose of duplicating them. This is a common practice in the field of physical science, but can be applied to software and even military technology.
With 3D scanning, reverse engineering can be accomplished easily. For example, if an old part needs to be remanufactured but its original design drawings no longer exist, a digital replica can be produced using the 3D scan. This can then be compared to the original part to ensure accuracy. This allows for more precise and efficient product manufacturing, saving valuable time and money.
This can also be useful for remanufacturing parts that originated before computer-aided design (CAD) software was available. It is a more cost effective method of producing accurate parts, as it eliminates the need to purchase expensive and sometimes inaccurate prototypes.
While it can be difficult to produce accurate models, especially for free-form or gradually changing shapes, with the right equipment it is possible. The basic 3D scanner digitizes the object as points in three-dimensional space, and with post processing can be converted to a triangulated mesh or a CAD solid model. This can then be used in a CAD program to recreate the original part.
In the field of software, reverse engineering is commonly used to analyze a program or its internal functioning procedures. By analyzing the program’s machine code—a string of 0s and 1s sent to the processor—and then translating that into programming language statements, engineers can understand how the code functions. This can help with troubleshooting, improving performance and understanding competitors’ programs.
Other purposes for reverse engineering include security auditing, removal of copy protection (cracking), circumvention of access restrictions present in consumer electronics (“hacking”), in-house repairs or retrofits and enabling additional features on low-cost “crippled hardware.” In some cases, this can be done for the sole sake of curiosity, but is often carried out by professional product developers and others who wish to gain a competitive advantage.
Inspection
The ability to convert physical objects into digital models opens up all sorts of possibilities. From 3D printing to video game design, the applications for reality capture are endless. There You Have It 3d’s work on a project to make 3D Printing possible for the iconic Brady Bunch house.
In fact, one of the most important uses of 3D scanning involves inspection. Whether it’s a piece of machinery, an airplane wing or a car frame, the ability to scan and then inspect parts makes production, repair and maintenance more efficient. Using a handheld scanner or even just a smartphone, users can quickly and easily capture a model of an object, then use a CAD program to analyze the part’s dimensions, shape and structure. This allows for quick and easy re-design, repairs or modification without the need to produce a new physical prototype.
For example, a team can use a mobile 3D scanner to create an accurate model of a machine or car part and then compare it to the original CAD file to check for accuracy. In this way, a problem can be identified and fixed before it leads to a costly mistake.
Another useful application for 3D scanning is remanufacturing old parts. 3D scanners can be used to make exact reproductions of parts that originated before computer-aided design (CAD) software was widely available, saving time and money in the remanufacturing process.
There are a number of different types of 3D scanners, which vary in their accuracy and cost. The most common are laser scanners which work by projecting a line of light onto the surface of an object and then recording how the light is distorted by the surface with a sensor. This data can then be used to create a 3D model of the surface.
Alternatively, structured light scanners work by projecting a series of patterns on to an object’s surface and then measuring how the pattern is distorted by the object. This information is then triangulated with the known camera position and can be used to construct a 3D model of the object’s surface. This type of 3D scanning is not as dependent on texture variation as laser or stereo vision, but it can still be difficult to use on shiny surfaces.
3D Printing
Three-dimensional scanning transforms physical objects into digital models that can be modified, shared, or used for many different applications. The process is used in a variety of industries, including manufacturing, architecture, film and video game development, and medical devices. It can also be used to preserve art and historical artifacts.
The most common use for 3D scanning is creating a digital model of an object that can be printed on a 3D printer. The resulting print will be a copy of the original object that has been made to a precise size and shape. This allows designers to make changes to the design without having to build a new physical prototype, which can be expensive and time-consuming.
3D scanning is also used for quality control in the production of mass-manufactured or handcrafted products, ensuring that the final product matches the original design. It can also be used for reverse engineering, where the original object is scanned to create a model that can then be compared with a CAD drawing of the original part. This is a powerful tool for speeding up industrial workflows, and can be particularly useful for small-scale production runs or for quickly catching errors in existing designs.
When choosing a 3D scanner, it is important to consider the accuracy and resolution required for the project. Scanning accuracy is measured by the distance between a pair of measured points, while resolution refers to the density of these points. High-resolution scanners are generally more accurate, but they can be more expensive.
There are a number of different types of 3D scanning equipment available, with some being more portable and lightweight than others. It is also important to choose a scanner that can handle the size of the object being scanned. For example, handheld laser and structured light scanners are suitable for capturing smaller objects, while professional-grade optical systems are better suited to larger-scale projects.
Some objects, such as metal or glass, cannot be scanned at all, while others can only be scanned with a certain level of accuracy. In these cases, it is recommended that the surface be sprayed with a temporary matte powder to improve scan quality.