A 3D scanner is a device that captures the shape and appearance of a physical object by collecting data on its surface. It uses various technologies, such as laser or structured light, to create a digital 3D model. This model can be used in various fields, including engineering, architecture, and art. 3D scanners are valuable tools for creating accurate representations of objects, which can be used for analysis, design, or reproduction. They help in tasks like reverse engineering, where existing products are scanned to understand their design, or in medical imaging, where they assist in creating prosthetics tailored to individual patients.