A 3D viewer is a software application or tool that allows users to visualize three-dimensional models and objects on a screen. These viewers can display various file formats, such as OBJ, STL, or FBX, and are commonly used in fields like architecture, engineering, and gaming. They enable users to rotate, zoom, and interact with models, providing a better understanding of spatial relationships. Many 3D viewers are available online or as downloadable applications, often featuring user-friendly interfaces. Some popular examples include Sketchfab, Blender, and Autodesk Viewer. These tools are essential for designers and developers to showcase their work effectively.