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The Learning Annex - More on Obstruction and Occlusion

Obstruction and occlusion are conditions that exist when the space between a sound source and a listener is blocked. Obstruction refers to a partial block, and occlusion to a complete block. These conditions are set up by the game developers, who programmatically define the geometry of the game. Wwise does not compute obstruction and occlusion levels by itself. The physics calculations must be done by the game and the results must then be passed to the sound engine using the following function: SetObjectObstructionAndOcclusion() .

In Wwise, you simply define the volume and LPF applied to sound objects as they are influenced by obstruction and occlusion during gameplay. The values you define are relative, and are added to any volume and LPF values already applied to the game object.

In the implementation of these conditions, percentage values are assigned to both obstruction and occlusion to enhance realism. These percentages are based on real-time positioning information from the game engine and can reflect a game object's movement in and out of a blocked area. For example, a spy character might move through an art gallery full of large sculptures. The percentage of obstruction could change depending on where she is as she passes behind each sculpture. Similarly, the percentage of occlusion could shift as the spy slowly sneaks out of a completely occluded broom closet.

[Note] Note

The percentage value calculations for obstruction and occlusion are handled by the sound engine. You do not specify these values in Wwise.

For a better understanding of when obstruction and occlusion occurs, refer to the following topics: