Time-Domain Acoustic Simulation With Chorded Modes and FFAT Maps
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Solution Overview
Problem
Conventional acoustic modeling techniques are computationally intensive and impractical for simulating the acoustic responses of digital objects, requiring hours to days of computation even for moderate-sized objects, making them infeasible for large numbers of objects in virtual environments.
Innovation Solution
The method involves conflating vibrational modes into chords and solving them in the time domain using a graphics processing unit (GPU) to accelerate the calculation of acoustic transfer functions, employing a structure-exploiting QR solver and FFAT maps for efficient storage and real-time rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional acoustic modeling techniques are used to calculate acoustic transfer functions, then measurement precision is improved, but productivity deteriorates due to computation taking hours to days
Solution Approach 1:
The patent transforms the acoustic transfer function calculation from frequency domain to time domain by changing the mathematical representation parameters. This allows using FFT-based methods that compute all frequency components simultaneously, reducing computation time from hours/days to minutes while maintaining accuracy through proper sampling and reconstruction algorithms
Solution Approach 2:
The patent pre-calculates and stores impulse response functions in the time domain before actual acoustic simulations are needed. These precomputed impulse responses can be rapidly convolved with any excitation signal during runtime, eliminating the need for repeated full-scale frequency domain calculations and enabling real-time or near-real-time acoustic rendering
2Manufacturing precision
If conventional acoustic modeling techniques are used, then manufacturing precision of acoustic models is improved, but loss of time increases due to hours to days of computation
Solution Approach 1:
By changing from frequency domain parameters to time domain impulse response parameters, the patent enables single-shot precomputation that captures all acoustic transfer characteristics. This eliminates the need for repeated frequency domain solves and allows rapid generation of accurate acoustic models for multiple objects in virtual environments
Solution Approach 2:
The patent creates simplified time domain impulse response copies of the full acoustic transfer functions. These compact impulse response representations can be stored and rapidly applied to multiple different excitation signals without requiring the original complex frequency domain models, significantly reducing computation time while preserving acoustic accuracy
3Adaptability or versatility
If the number of objects in virtual environments increases, then adaptability is improved, but productivity deteriorates due to infeasibility of conventional methods for large numbers of objects
Solution Approach 1:
The patent pre-computes and caches impulse response functions for each object in the virtual environment during an offline preparation phase. During runtime, when objects are interacted with, the system simply retrieves the precomputed impulse responses and performs fast convolution operations, enabling hundreds or thousands of objects to be simulated simultaneously without proportionally increasing computation time
Solution Approach 2:
By representing acoustic transfer functions as time domain impulse responses rather than frequency domain transfer functions, the patent reduces the computational complexity from O(N²) frequency domain solves to O(N) impulse response convolutions, where N is the number of objects. This parameter transformation makes it feasible to include large numbers of acoustic objects in virtual environments
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces computational power, enabling acoustic simulation orders of magnitude faster, allowing for real-time rendering of acoustic responses in virtual environments.
Implementation Method 1
calculating, for each chord, a chord sound field in the time domain, where the chord sound field describes acoustic pressure surrounding the object when the object oscillates in accordance with the subset of the plurality of vibrational modes
Data Source
AI summary
Systems and methods for acoustic simulation in accordance with embodiments of the invention are illustrated. One embodiment includes a method for simulating acoustic responses, including obtaining a digital model of an object, calculating a plurality of vibrational modes of the object, conflating the plurality of vibrational modes into a plurality of chords, where each chord includes a subset of the plurality of vibrational modes, calculating, for each chord, a chord sound field in the time domain, where the chord sound field describes acoustic pressure surrounding the object when the object oscillates in accordance with the subset of the plurality of vibrational modes, deconflating each chord sound field into a plurality of modal sound fields, where each modal sound field describes acoustic pressure surrounding the object when the object oscillates in accordance with a single vibrational mode, and storing each modal sound field in a far-field acoustic transfer (FFAT) map.