Why are three-dimensional objects often built from lines, triangles, and polygons in computer graphics?

In computer graphics, three-dimensional objects are built from lines, triangles, and polygons because these geometric primitives provide a necessary computational framework for modeling and rendering complex scenes. While bitmaps are used for final display, they are generally inappropriate for the computational tasks required to manipulate 3D models.1

Using polygons and line segments allows computers to represent objects as "wire-frame" models, which can be mathematically transformed as they move or rotate relative to an observer's viewpoint. This structure is essential for:1

• Hidden Surface Elimination: Algorithms can compute which surfaces are visible and which are obscured by others based on the depth of these geometric components.1
• Computational Efficiency: Representing objects through these primitives allows for the efficient calculation of lighting, shading, and surface textures.1
• Real-time Rendering: Modern graphics hardware is optimized to process these polygons rapidly, enabling interactive applications like electronic games to render scenes without perceptible lag.1

While smoother representations like Bezier curves exist, polygons remain a standard, fundamental building block for constructing and analyzing 3D models within computer programs.1