Stanford University, Spring 2021
CS 448Z: Physically Based Animation and Sound

Instructor:
Prof. Doug James

Inverse-Foley Animation: Synchronizing rigid-body motions
          to sound ACM SIGGRAPH 2014

Description:
Intermediate level, emphasizing physically based simulation techniques for computer animation and synchronized sound synthesis. Topics vary from year to year, but include the simulation of acoustic waves, and integrated approaches to visual and auditory simulation of rigid bodies, deformable solids, collision detection and contact resolution, fracture, fluids and gases, and virtual characters. Students will read and discuss papers, and do programming projects.

Location
Remote, Tu/Th 4:30 PM - 5:50 PM  (see Canvas for links)
Prerequisites
None. Recommended: Prior exposure to computer graphics and/or scientific computing.
Textbook
None; lecture notes and research papers assigned as readings will be posted here.
Communication
Piazza: https://piazza.com/stanford/spring2021/cs448z/home
Requirements
Students are expected to attend the lectures and participate in class discussions, and read the supplemental materials.
Assignments
There will be readings, programming assignments, and a final project based on a student-selected topic.
Exams
None.



SYLLABUS (Topics chosen from)
PROGRAMMING PROJECTS (Spring 2021)
SCHEDULE (Spring 2021)
DATE
TOPIC
SUPPLEMENTAL MATERIALS
TuMar30
Introduction
Slides (PDF)
ThApr01
HW0: Code Warm-up!

ThApr01
TuApr06
Sound waves and radiation modeling
Topics: Eqn of continuity; momentum equation; eqsn of linear acoustics; velocity potential; incompressible fluids; pulsating bubble; free-space Green's function; general solution; point sources (monopole, dipole, quadrupole); power; acoustic far-field radiation; Fraunhofer approximation; translating/vibrating sphere

References:
Additional background reading:
  • Bridson, R., Fedkiw, R., and Muller-Fischer, M. 2006. Fluid simulation: SIGGRAPH 2006 course notes, In ACM SIGGRAPH 2006 Courses (Boston, Massachusetts, July 30 - August 03, 2006). SIGGRAPH '06. ACM Press, New York, NY, 1-87.  [Slides, Notes]
    • See "Appendix A Background" (of the Notes) for a good primer on vector calculus for fluids.
ThApr08
TuApr13
Acceleration noise for rigid-body impacts

Topics: Rigid-body acceleration; Hertz contact and impact time scale; acceleration noise pulses; precomputation; rendering details.

References:
TuApr13
TuApr20
Homework 1:
Real-time Rigid-Body Dynamics
with Acceleration Noise

ThApr15
Collision Detection

Slides (PDF)
TuApr20
Modal vibration analysis
& sound synthesis
Topics: Simple harmonic oscillator, mass-spring systems; modal vibration of 3D solids; mass and stiffness matrices; meshing and discretization; generalized eigenvalue problem; eigenfrequencies and eigenmodes; eigensolvers for large systems; damping models; time-stepping modal vibrations; integration with rigid-body dynamics engines.

Slides: PDF, key, Notes(PDF)

References:
ThApr22
Fire Sound
Slides (PDF)

Reference:
TuApr27
ThApr28
Liquid Sound
Materials:
ThApr29
Aerodynamic Sound

Slides (PDF)

References:


































PAST PROGRAMMING PROJECTS (Winter 2015)
  1. Warm-up!: Audiovisual code warm-up using using openFrameworks
  2. Real-time rigid-body dynamics with acceleration noise (3 weeks; due Oct 22)
  3. Real-time rigid-body dynamics with modal sound (3 weeks; due Nov 12)
  4. Final project (student choice; final presentation Dec 3; due Dec 11)

SCHEDULE (Winter 2015)
DATE TOPIC SUPPLEMENTAL MATERIALS
TuSep22 Introduction
Slides (PDF)
ThSep24
TuSep29
Sound waves and radiation modeling

Topics: Eqn of continuity; momentum equation; eqsn of linear acoustics; velocity potential; incompressible fluids; pulsating bubble; free-space Green's function; general solution; point sources (monopole, dipole, quadrupole); power; acoustic far-field radiation; Fraunhofer approximation; translating/vibrating sphere

References:
  • Whiteboard notes
  • M. S. Howe. (2002). Theory of Vortex Sound. [Online]. Cambridge Texts in Applied Mathematics. (No. 33). Cambridge: Cambridge University Press. Available from: Cambridge Books Online <http://dx.doi.org/10.1017/CBO9780511755491>
    • Chapter 1, Introduction.
Additional background reading:
  • Bridson, R., Fedkiw, R., and Muller-Fischer, M. 2006. Fluid simulation: SIGGRAPH 2006 course notes, In ACM SIGGRAPH 2006 Courses (Boston, Massachusetts, July 30 - August 03, 2006). SIGGRAPH '06. ACM Press, New York, NY, 1-87.  [Slides, Notes]
    • See "Appendix A Background" (of the Notes) for a good primer on vector calculus for fluids.
ThOct01
Acceleration noise for rigid-body impacts

Topics: Rigid-body acceleration; Hertz contact and impact time scale; acceleration noise pulses; precomputation; rendering details.

References:
ThOct01
Homework 1:
Real-time Rigid-Body Dynamics
with Acceleration Noise

  • PDF
  • Due in 3 weeks.
TuOct06 Rigid-body dynamics & contact modeling

Topics: Animation background; equations of motion; discrete-time integration; collision detection; contact resolution strategies.
ThOct08 Acceleration noise for rigid-body impacts (cont'd)
TuOct13 Constraints & rigid-body contact

Topics: Constrained dynamics; post-step stabilization (quaternion example); rigid-body contact problem; equality and inequality constraints; linear complementarity problems.

References:
ThOct15
TuOct20
Modal vibration analysis
& sound synthesis

Topics: Simple harmonic oscillator, mass-spring systems; modal vibration of 3D solids; mass and stiffness matrices; meshing and discretization; generalized eigenvalue problem; eigenfrequencies and eigenmodes; eigensolvers for large systems; damping models; time-stepping modal vibrations; integration with rigid-body dynamics engines.

References:

ThOct22 Homework 2:
Real-time Rigid-Body Dynamics with Modal Sound
TuOct27
ThOct29
TuNov03
Acoustic transfer for modal vibrations

Topics: Transfer function definition; multipole expansions; solvers and precomputation; fast evaluation; rendering details.

References:
TuNov03
ThNov05
TuNov10
Fracture

References:

ThNov12
TuNov17
Fluid Animation

Materials:
TuNov17 Liquid Sounds

Materials:
ThNov19 Turbulence & Fire Sound

Materials:
TuNov24
ThNov26
Thanksgiving Recess (no class)


TuDec01
Project working session
In-class working session. Come prepared to discuss your progress and problems with Prof. James.
ThDec03
Project presentations & discussions

FriDec11
Final projects due
Last day to submit your final project (HW3) on Canvas.