Game developers often employ Screenspace Ambient Occlusion (SSAO) with enthusiasm, leading to visual artifacts like brighter convex corners and "bizarre halos." The author, Sean Barrett, argues that SSAO frequently produces unrealistic results, particularly making room corners appear "weirdly dark." This perceived darkness, he suggests, stems from a misconception that real-world corners are inherently dark, influencing developers to code accordingly. Barrett attributes SSAO's failures to four factors: approximation errors from using SSAO instead of Ambient Occlusion (AO) or radiosity, incorrect application of darkening to all lighting, and "tuning errors" where the AO effect is overemphasized.

To illustrate his points, Barrett presents photographs of real-world corners, contrasting them with typical SSAO renderings. He analyzes specific photographic examples, explaining that observed darkening is often due to soft shadows from light sources or indirect lighting effects, rather than solely AO. He meticulously breaks down the lighting in a photographed corner, demonstrating how shadows and the geometry of light sources contribute to perceived darkness. Barrett also graphs pixel values across edges in his photographs to visually represent the darkening effects, comparing them to what might be expected from AO. Despite acknowledging potential limitations in his photographic data and analysis, he maintains that real-world visual experience often diverges significantly from SSAO's output, especially concerning the rendering of corners.