3D modeling is used in various industries like medicine, engineering, product design, architecture, and interactive media and games. It involves using polygons, which are shapes with 3 or more points, to create models. Common 3D modeling programs discussed are Autodesk 3DS Max, Autodesk Maya, LightWave 3D, and Blender, which allow creating 3D content through modeling, animation, and rendering capabilities. However, 3D modeling is constrained by hardware limitations as complex models require high-powered computers to handle increased polygon counts and detail.