CS488 - Introduction to Computer Graphics - Lecture 33

Modelling

Animation

Physics

Interactive Animation

Critical times

• cycle times for smooth animation
  • temporal frequency response function: 30 msec
  • image update time
• response times for actions
  • simultaneity: 100 msec
  • content change update time

Human responses when these criteria are not met.

• Hardware designed to make meeting these times possible.
• So it's just up to the software you write to render fast enough.

Force Feedback

Critical test

• bang on a wall

Critical times

• cycle times for smooth animation
  • temporal frequency response function: 0.5 msec
• response times for actions
  • simultaneity: 0.5 msec
• synchronization with video
  • cross-modality simultaneity: 100 msec

How are these criteria met in current technology?

• microcontroller for device
  • cycle time 1msec
• pre-canned programs called `effects'
• start of effect synchronized to video: 100 msec
• Animation has an effect stream that releases effects at requested times

What exactly is a frame buffer?

• mediates between different update times
  • update time for frame: 30 msec
  • update time for video signal: 10 nsec
• how is it done?
  • two distinct processors with independent clocks
  • dual-ported memory
    • containing forces
    • forces depend on state of a probe

We can use the same idea for force

• dual-ported memory called force buffer
• updated by application on 100 msec cycle

Return to:

• Bill Cowan's teaching page.
• Bill Cowan's CS488 page for Winter 2009.
• Bill Cowan's CS488 lecture note page for Winter 2009.