Shading in computer graphics refers to the process of assigning colors to pixels or vertices in a 3D model. It involves simulating the way light interacts with surfaces, determining how light and shadow create the final appearance of an object. Proper shading is essential for achieving realism in rendered images or animations.

Different shading models exist, including flat shading, Gouraud shading, and Phong shading, each offering varying levels of complexity and realism. Flat shading applies a single color to each polygon, while Gouraud shading interpolates colors across vertices, and Phong shading calculates shading at each pixel, providing smoother and more realistic results.