Occlusion

Occlusion, in interactive audio, describes the case where geometry blocks both the direct and the reflected paths between a source and the listener, as when a sound is sealed behind a thick wall. Both the direct sound and its reverberation are attenuated and filtered, producing a strongly muffled and distant impression.

Engines distinguish occlusion from obstruction because the two call for different treatment, with occlusion reducing the entire signal rather than only the direct path. Modeling it convincingly helps players judge that a source is enclosed or separated from them by solid material, which supports both realism and gameplay awareness.^[1]