3d scanning and reengineering

The development of 3d-scanning technology brings us closer and closer to higher-quality scanning of three-dimensional objects and obtaining high-quality 3d-models of them. The quality of such models becomes so detailed that they can be used to develop drawings and put them into production. Today it is possible to scan both small details and huge buildings, while the model is immediately built on the monitor screen.
With such rapid development, 3D scanning finds application in almost all industries and manufacturing, from the souvenir industry to complex medical and space industries.

The main 3d scanning tool is the 3d scanner . This is a peripheral device that analyzes a physical object and, based on the data obtained, creates a 3d model of it. The 3D scanner is a great tool for reverse engineering .

Reverse engineering (reverse engineering or reverse engineering) is the development or recreation of an existing product or documentation for it in order to understand how it works.

Development of a product from scratch, especially an artistic product, is a rather laborious process, it requires determining the size of all parts and creating 3d models for them. Accordingly, artistic elements are even more difficult to measure and reproduce accurately.

3d scanning allows you to do this in minutes or even seconds. Moreover, the shape and size of the products does not matter. It is possible to scan absolutely any product, no matter how complex surfaces they have, and even the person himself and the work of art. This is the beauty of 3d scanning and its technologies.

Types of scanners

Scanners are distinguished by the scanning method: contact and non-contact.

Contact scanners involve the contact of the scanner probe with the product. They represent a fairly simple scanning process independent of lighting, but they are difficult to scan large objects and also cannot capture the texture of the object.

Non-contact scanners are divided into active and passive.

Active scanners emit some directional waves (light, laser) on the object and determine their reflection.

Passive scanners do not emit anything at the object; they detect the reflection of the surrounding radiation.

The device and principle of operation of a 3d scanner

The scanner device includes cameras, with the help of which the scanner determines the distance to the object from different angles and compares the images transmitted by these cameras. The principle of stereo vision is used, just as a person with the help of two eyes determines the distance to the object, the 3d scanner uses two cameras to calculate the coordinates of the points of the object. For higher accuracy and reliability, in addition to cameras, illumination devices are used.

If the scanner is based on the operation of a laser beam, then with its help the distances at specified points are determined; this type of scanner is based on a time-of-flight laser rangefinder.

Based on the analysis of the obtained data, the computer forms a 3d-model of the scanned object.

Optical and laser scanners have their own capabilities and limitations, so scanning a person with a laser scanner is almost impossible, and optical ones are not suitable for scanning mirror-like and transparent or shiny products, but are excellent for scanning a person.

The result of a 3d scan is a polygonal model or a point cloud in the .stl, .ply, .obj format.

But it is difficult to use it in this form, it is essentially a point cloud , that is, a set of vertices in a three-dimensional coordinate system, specified by the coordinates X, Y, Z and designed to represent the outer surface of an object.

But based on this model, you can get a complete CAD model . To do this, you can use various CAD systems that allow converting the .stl format to the CAD system format or the transitional formats .step, .igs, .sat, .x_t, etc.

If the model is complex, then not all CAD systems will allow you to do this. It is possible to apply the following method. Using a system, for example, FreeCAD or another, based on the stl-model, build a surface mesh.

And convert the resulting mesh into a solid and export it to the intermediate format we need. Further, the model can be edited with any CAD-systems.

This is how quickly and easily you can get 3d-models of existing products. Developing a model manually with a caliper measurement would take much more time and effort.

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