A normal map is a texture used in 3D graphics to simulate the effect of bumps and dents on a surface. Rather than adding more polygons to a model, it alters the direction light reflects, creating the illusion of a more detailed surface. Imagine a flat wall: a normal map can make it appear to have bricks or intricate patterns carved into its surface. This illusion is achieved by storing surface normal vectors (directions perpendicular to the surface) in the red, green, and blue channels of an image.
Utilizing these textures enhances the visual fidelity of 3D models without drastically increasing polygon count, which is crucial for performance, particularly in games and real-time applications. This technique allows for more detailed environments and characters without compromising speed or efficiency. The concept has become a cornerstone in modern 3D rendering pipelines, enabling developers to achieve photorealistic effects even with relatively low-poly models. Its evolution has significantly improved the quality and complexity of visuals in various applications, from video games to architectural visualizations.