Interactive Character Animation using Simulated Physics T. - - PowerPoint PPT Presentation

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Interactive Character Animation using Simulated Physics T. - - PowerPoint PPT Presentation

Jun 22, 2023 265 likes •417 views

Interactive Character Animation using Simulated Physics T. Geijtenbeek, N. Pronost, A. Egges, and M. H. Overmars Given by Derek Basehore Why use Physics? Responses to Actions in the simulated environment do not rely on existing data

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SLIDE 1

Interactive Character Animation using Simulated Physics

  • T. Geijtenbeek, N. Pronost, A. Egges, and M. H.

Overmars Given by Derek Basehore

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SLIDE 2

Why use Physics?

  • Responses to Actions in the simulated

environment do not rely on existing data (kinematics)

  • Can create unique reactions depending on the

stimulus

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SLIDE 3

How?

Row 1 Row 2 Row 3 Row 4 2 4 6 8 10 12 Column 1 Column 2 Column 3

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SLIDE 4

Overview

  • Forward Dynamics vs. Inverse Dynamics
  • Actuation Modeling
  • Motion Controllers
  • Optimization
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SLIDE 5

Forward Dynamics

  • Compute the accelerations of simulated
  • bjects
  • Based directly off of simple physics equations

L=mv H =Iw q' '=M (q)

−1(c(q ,q')+T (q)τ+e(q))

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SLIDE 6

Inverse Dynamics

  • Opposite of forward dynamics
  • Instead of taking accelerations, you take a

motion and find the acceleration needed to perform that motion.

  • Motion data is analyzed to determine which

motions to use

τ=T (q)

−1(M (q)q' '+c(q ,q')+e(q))

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SLIDE 7

Different Actuation Models

  • Muscle-Based Actuation
  • Servo-Based Actuation
  • Virtual Forces
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SLIDE 8

Muscle-Based Actuation

  • Computationally expensive, so real time

simulations typically do not use it

  • Need at least 2 muscles for every degree of

freedom since muscles can only pull (hence more computationally intensive)

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SLIDE 9

Servo-Based Actuation

  • Every joint is controlled by a servo motor
  • Can lead to more unnatural looking animation

when optimization is used (as opposed to muscle-based actuation)

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SLIDE 10

Motion Controllers

  • Use sensor data to control the motion of the

character

  • Joint State, Contact Information, Center of

Mass, Target Position, etc.

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SLIDE 11

Joint-Space Motion Control

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SLIDE 12

Stimulus-Response Network Control

  • Creates strict relations between sensors and

actuators

  • Relies heavily on optimization

– often uses evolutionary algorithms for offline

  • ptimization and reinforcement learning for
  • nline optimization
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SLIDE 13

Videos of Research Projects

  • http://www.youtube.com/watch?v=JBgG_VSP7f8
  • http://people.csail.mit.edu/jovan/assets/movies/abe-2007-mcf.mp4