Hello everyone. I hope you are doing all right. Today, we start the second week of our online course, theme 1: 3D scanning. 3D scanning for printing a three-dimensional object using a 3D printer. At the beginning, it is needed to make its three-dimensional model a visual graphic image of the object. Previously, modeling was carried out only manually using special software. A 3D scanner was invented to speed up and simplify the modeling process. Three-dimensional scanning makes it possible to obtain a complex three-dimensional model of the studied object. 3D scanner is a device designed to reproduce the form of any physical object in digital format in order to build its virtual three-dimensional model. 3D scanner digitizes the object that allows making its mathematical model for subsequent printing using a printer. The device creates a cloud of points connected by lines which form the object geometry from many intersecting planes. The obtained coordinates are processed and saved as a parametric model. It is possible to work with it in any CAD system to create drawings of individual elements of an object, to modify it, to correct dimensions and other parameters necessary for printer programming. A distinction is made between two volumetric scanning methods: contact and non-contact. The device is surrounded by an object and each arch is examined with a special stylus. That traditional bridge measuring machine, as it is commonly called, is a three-axis measuring machine with x, y, and z-axis. The axis are orthogonal to each other and form the usual three-dimensional coordinate system. Each axis has its own scale which determines the location of the axis. The machine reads the data from the sensor as it is instructed by the operator or computer. The machine then uses the x, y, z coordinates of each of these points to determine the size and location. The six-axis coordinate measuring machine hexapod is based on parallel kinematics. Unlike the triaxial one, it has no portals or bridges. Structurally, the SMM is a parallel structure in the form of an inverted truncated pyramid. There are spherical joints at the base of the pyramid which serve as the reference points for the measuring system. The six probes are directly connected to the moving carriage, where the probe head is located. Typically, the accuracy of a coordinate machine is in the order of microns or micrometers, which is one-millionth of a meter. One of the advantages of such scanning is independence from lighting conditions. But there are a number of disadvantages. Control and measuring machine does not distinguish between the textures and has limitations on the size of the measured object. The 3D contact scanner works to the touch. The non-contact 3D scanning method is divided into two sub-types: active and passive. The active 3D scanners use ultrasound, a directional light source, a laser, or x-rays to irradiate the investigated object. The device calculates the time of signal return, forming a coordinate system from the points of contact with the object and the distance to the scanner. The operator scans the object from different angles and the software glues the parts together. Advantages of 3D scanner of active type are as following: it is easy to use, the process is carried out without physical contact with the object, it works inside and outside the room, and it does not depend on lighting. At the same time, there are significant disadvantages. The scanner is unable to work with mirror surfaces and transparent objects because the powerful optics are required to work with small products. A passive 3D scanner is still the same digital video camera that captures the studied object from different angles, catching its silhouette. It works only with high-contrast backgrounds and in good light. The footage is processed by software and reduced to a 3D model for printing using a printer or CAD processing. The three-dimensional model of the object obtained from the scanner or control and measuring machine can be modified, improved, resized, etc. Then, the part or product can be produced using this model. 3D scanning has found wide application in reverse engineering. With a worn or broken part, it is possible to obtain a digital model quickly and produce it by traditional machining or by 3D printing, i.e., additive technology.