Extreme ambient occlusion (AO) is a technique used in computer graphics to enhance the realism of rendered images by accurately representing shadows and ambient lighting in complex and detailed scenes. It involves simulating and increasing the amount of occlusion, or blocking of light, in areas where objects are close together or intersecting. This helps to create more realistic and atmospheric lighting effects, leading to more visually appealing and immersive graphics. Extreme AO is often used in video games, architectural visualization, and other applications where realistic lighting and shadows are crucial for creating realistic and immersive environments.