Audio Tracing – Unreal Engine
Audio Tracing
Real-Time Hardware-accelerated Ray Traced Audio Plugin.
Audio Tracing is a plugin that integrates real-time Ray Tracing technology into Unreal Engine’s Sound system with the goal of achieving more realistic sound propagation simulation. It physically calculates complex acoustic properties—such as the position, direction, and reflections of sound sources within a real-time, changing game environment—and applies them to the listener, providing a realistic and spatial sound experience.
This plugin automatically calculates sound reflections and occlusion via real-time ray tracing. This approach makes it possible to implement realistic sound variations based solely on the world’s geometry, without the need to set up separate audio occlusion volumes or complex Blueprint logic.
Users can apply Audio Tracing to existing sounds with only minimal modifications, as it is compatible with Unreal Engine’s existing Sound Asset system, including SoundCues and MetaSounds.
Additionally, the Sound Material feature allows for detailed adjustment of the acoustic properties of each surface. You can specifically define the acoustic response of each surface by individually setting scattering coefficients, reflectivity, and absorption coefficients for materials such as wood, glass, and concrete.
Notice:
The assets included in this Sample Project are provided for demonstration purposes only.
They must not be reused, redistributed, or included in other projects (commercial or non-commercial) without proper authorization.
Best Practices for Optimal Audio Accuracy
For the most accurate and stable audio transmission, we recommend ensuring a clear spatial relationship between sound-affecting surfaces. A slight, intentional overlap or a small gap helps our ray tracer to resolve surface ambiguity perfectly, preventing potential inconsistencies and guaranteeing physically correct results in all situations.
Please also note that the player character mesh can be affected by ray tracing. You can verify this by checking if the mesh appears on the Sound Material Debug view.
This can be enabled with the following console command:
To enable: AudioTracing.HardwareRayTracing.DebugSoundMaterial 1
To disable: AudioTracing.HardwareRayTracing.DebugSoundMaterial 0
Recommended Specifications
A DirectX 12 compatible graphics card with support for ray tracing is required.
Specifications used for development:
CPU: Intel i7-14700 2.10GHz
GPU: NVIDIA GeForce RTX 4060
Memory: 32GB
Graphics RAM: 8GB
Available Console Variables
AudioTracing.SoundSpeed
AudioTracing.HeadWidth
AudioTracing.CustomPrimitiveDataStartSlotIndex
AudioTracing.ShowDebugVirtualAudio
AudioTracing.MinUpdateInterval
AudioTracing.HardwareRayTracing
AudioTracing.HardwareRayTracing.MaxReflectionDepth
AudioTracing.HardwareRayTracing.MaxTraceTime
AudioTracing.HardwareRayTracing.MaxActiveSoundSources
AudioTracing.HardwareRayTracing.RayTracingNormalBias
AudioTracing.HardwareRayTracing.DebugSoundMaterial
Known Issue
If sound does not propagate correctly in enclosed spaces, make sure that the mesh supports Ray Tracing. AudioTracing relies on the same geometry used for GPU Ray Tracing, so if the mesh does not support it, AudioTracing will not function properly.
AudioTracing provides a default Attenuation Asset. Since AudioTracing builds upon Unreal Engine’s native Attenuation system to perform post-processing on audio, any custom attenuation effects set by the user will take precedence and be applied before AudioTracing processing.
Required Modules
Metasound
Synthesis
Disclaimer
This product was independently developed by me(us) while participating in the Epic Project, a developer-support program of the KRAFTON JUNGLE GameTech Lab. All rights, title, and interest in and to the product are exclusively vested in me(us). Krafton, Inc. was not involved in its development and distribution and disclaims all representations and warranties, express or implied, and assumes no responsibility or liability for any consequences arising from the use of this product.
Features:
Hardware-Accelerated Sound Simulation: Simulates multi-bounce reflections and thickness-based transmission utilizing the engine’s hardware ray tracing pipeline.
Per-Instance Acoustic Material System: Defines reflection, scattering, and absorption properties on primitive components. Data is delivered to shaders via Custom Primitive Data, with a configurable start-slot index for compatibility.
Code Modules:
Core
Engine
DeveloperSettings
AudioMixer
SignalProcessing
MetasoundEngine
CoreUObject
Slate
SlateCore
EditorSubsystem
Projects
ToolMenus
Blutility
RHI
Renderer
RenderCore
Synthesis
AudioExtensions
Number of Blueprints: 0
Number of C++ Classes: 9
Network Replicated: No
Supported Development Platforms:
Windows: Yes
Mac: No
Supported Target Build Platforms: Windows
Supported Unreal Engine Versions: 5.6
Important/Additional Notes: This plugin’s core functionality relies on the engine’s Hardware Ray Tracing pipeline. This pipeline is activated in the renderer when either the Global Illumination Method or the Reflection Method is set to Lumen.
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