Geometric Modeling of Sound Propagation in 3D Environments · 2004. 4. 20. · Small wood corridor Small metal room Unreal Tournament, Epic / GT Interactive 1999 Alone in the Dark

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Geometric Modeling ofSound Propagation in

3D Environments

Geometric Modeling ofSound Propagation in

3D Environments

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Computer Science DepartmentPrinceton University

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Computer Science DepartmentPrinceton University

Goal

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0-10 ms

90-100 ms

30-40 ms

120-130 ms 150-160 ms

60-70 ms

Stettner92

Sound Source

Motivation

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Evans & Sutherland

Vartek NV

Motivation

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Epic / GT Interactive 1999

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Small wood corridor Small metal room

Unreal Tournament, Epic / GT Interactive 1999

Alone in the Dark 4, Darkworks/Infogrames, 2000

Motivation

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Moves InstituteEverquestMoves Institute

Audio Rendering

Input Audio Signals

AcousticModeling

Output Audio Signal(s)

Source Receiver

VirtualEnvironment

AuditoryDisplayA

mpl

itude

Time Delay

Impulse Response

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Talk Outline

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Acoustic Modeling Overview

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= wave theory approximation

Stettner92


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= ray theory approximation

PropagationPaths


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τ1

τN

τ 2

g1

gN

g2

A

delay attenuation

feedback matrix

Feedback Delay NetworkJot


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plitu

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Time DelayDirectSound

EarlyPropagation

LateReverberation

ArtificialReverberation

GeometricPath Tracing

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Time DelayDirectSound

EarlyPropagation

LateReverberation

ArtificialReverberation

GeometricPath Tracing

Geometric Path Tracing

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Beam Tracing Method

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Papers atSIGGRAPH

1998, 1999, 2001

Talk Outline

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Beam Tracing Method

Cell Adjacency Graph

Spatial Subdivision

StationarySources

SourceAudio

Beam Trees

Beam Tracing

Propagation Paths

Path Generation

Auditory Display

MovingReceiver

Off-LineInteractive

3D Environment

Spatialized Audio

Step 4: Auralization

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source

receiver

Beam Tracing Method

Cell Adjacency Graph

Spatial Subdivision

StationarySources

SourceAudio

Beam Trees

Beam Tracing

Propagation Paths

Path Generation

Auditory Display

MovingReceiver

Off-LineInteractive

3D Environment

Spatialized Audio

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Beam Tracing Demo Experimental Results

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Beam Tracing Results

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200000

300000

400000

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

# Polygons in Environment

# B

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efle

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Path Generation Results

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# Polygons in Environment

Pat

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ime

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10,057 input polygons8 specular reflections6 updates per second

195MHz CPU (1998)

Path Generation Video Path Generation Demo

Reflection pathsupdated interactively

StationarySource

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Auralization Video I

Specular reflection only

Auralization Video II

Diffraction and specular reflection

Diagnostic Results

Paths

Power Power + Paths

Diagnostic Results

Specular Reflection + Diffraction

Specular Reflection Only

Diffraction Only

Diagnostic Results Talk Outline

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Multi-Player Game System

AudioServer

Client B Client D

Client CClient A

Network

Player Audio& Viewpoints

Spatialized Audio Network

Moving Sources & Receivers

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Real-Time Beam Tracing

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Audio

Receiver

Audio

SourcePath Generation

Sequence Construction

Beam Tracing

Real-Time System Organization

Avatar Regions

Motion Prediction AvatarViewpoints

AvatarAudio

Conservative Beams

Beam Tracing

Traversal Sequences

Sequence Construction

Reflection Paths

Path Generation

Auralization Spatialized

Audio

~10 Hz

~100 Hz

GlobalPriority Queue

Amortized Beam Tracing

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Beams from box over-estimate paths from points in boxBeams from box over-estimate paths from points in box

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Priority-Driven Beam Tracing

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400 beams with shortest paths to “B”400 beams with shortest paths to “B”

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Bidirectional Beam Tracing

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Beams from “A” (up to 2 reflections)

Beams from “A” (up to 2 reflections)

Beams from “B” (up to 2 reflections)

Beams from “B” (up to 2 reflections)

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Surface intersectionSurface intersection

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Propagation pathPropagation path

BB

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Path Generation

Bidirectional sequencing

Beam Tracing

Predictive Time-Critical Computing

Avatar Regions

Motion Prediction AvatarViewpoints

AvatarAudio

Conservative Beams

Beam Tracing

Traversal Sequences

Bidirectional sequencing

Reflection Paths

Path Generation

Auralization Spatialized

Audio

~10 Hz

~100 Hz

GlobalPriority Queue

of Beams

Real-Time Beam Tracing Video

Specular reflection only

Summary

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Limitations of Current Method

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Future Work

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Geometric Modeling of Sound Propagation in 3D Environments · 2004. 4. 20. · Small wood corridor Small metal room Unreal Tournament, Epic / GT Interactive 1999 Alone in the Dark