Trilinear filtering is a texture filtering technique used in computer graphics to improve the quality of images rendered on 3D surfaces. It works by blending textures from multiple mipmap levels, which are pre-calculated, downscaled versions of a texture. This helps to create smoother transitions and reduce the appearance of pixelation when textures are viewed at varying distances. When a 3D object is rendered, trilinear filtering samples the nearest mipmap levels based on the distance from the camera. By averaging these samples, it provides a more natural look, especially in scenes where objects are moving closer or further away. This technique is commonly used in video games and simulations to enhance visual realism.