Wwise Unreal Integration Documentation
Diffraction

When the line of sight between the emitter and the listener is obstructed by an object, Spatial Audio can create diffraction paths that will go around the object and simulate a realistic behavior. Depending on the angle of the path around an edge, the sound will be attenuated with obstruction.

Note:
The Preparation for the Spatial Audio Tutorials must be completed prior to starting this tutorial.
Note:
When using Spatial Audio diffraction, disable unreal engine side obstruction/occlusion. Set the Occlusion Refresh Interval of your emitters (AkComponent) to 0.
  1. In the Wwise project, make sure that diffraction is enabled on the Sound SFXs that are emitted by the emitters we want to use diffraction for.
    1. Enable Diffraction in the Positioning tab of the Sound Property Editor.
  2. In Unreal,
    1. Click on each AkAmbientSound actors that will be emitting diffraction enabled sounds.
      1. Set Occlusion Refresh Interval to 0.
    2. If not done already, add an AkSpatialAudioVolume object around the building.
      1. Make sure that Enable Surface Reflectors is enabled.
      2. In the Geometry Settings section, make sure Diffraction is enabled.
    3. If not done already, add an AkGeometry component to the obstacle static mesh outside.
      1. In the Geometry section, under Diffraction, make sure Diffraction is enabled.
  3. Generate SoundBanks.
  4. Play and connect to Wwise.
    1. You should be able to see diffraction edges on the diffraction-enabled geometries and diffraction paths when a diffraction-enabled sound is played while it is obstructed from the listener.

In the SpatialAudioTutorialMap provided with the Demo Game, you can see the diffraction paths created by the obstacle outside when the outside emitter is playing:

Diffraction Paths in the Game Object 3D Viewer
See also