Computer Generated Imagery in "Live" video

Movies these days rely heavily on CGI effects because they are relatively inexpensive, and highly effective ways to create believable animated characters that can interact with "live" action footage

This tutorial will take you through the process

"Live" footage has been shot in class and stored on the handouts server
A single frame of the footage has been saved as a reference image

Your job is to set up your alien in a scene that matches the live "set", and create animation that can be overlayed (composited) in Premiere to make it appear that the alien interacts with the live footage.

1. Create a Scene to match the "Real" world video
  • Load in the REFERENCE image from the handouts folder as a background
  • Match the Camera pitch (-20 degrees), height and rotation to match

2. Create the general motion
  • Create a crude ANIMATIC of the desired action
  • Build in a Walk Cycle and apply it to establish proper timing

3. Add subtle animation
  • Add Morphed Expressions at appropriate time

4. Set up the Green Floor, Props & Background
  • Create a simple tabletop object, and perhaps a keyboard object to help "catch" shadows and obscure parts of your character as he walks across the desktop
  • Create a Green material colour to colour your virtual "props":
    • Use 0 red, 255 green and 0 blue - 0 lightness, 255 saturation, 0 black
    • Start with .3 Ambient and .7 Diffuse settings
      The trick is to create greenscreen props that will blend in as much as possible with the greenscreen background, but still be able to catch shadows from your character. Higher AMBIENT values will make it blend in better, but eliminate the shadows that result from the DIFFUSE value.

5. Render the CGI footage (ALIASED at first) - instead of DIVX, try using LAGARITH if you have it.
DIVX version

Alien Deskwalk Cinepak test from Jeff May on Vimeo.

Edges are a bit jaggy, character appears "interlaced
LAGARITH version

Alien Deskwalk Lagarith test from Jeff May on Vimeo.

Edges are clean, character is solid
(Expand these movies to full screen to see the difference in quality)

6. "Test fit" the CGI with the Live footage in Premiere

7. Once the animation is perfected, render an ANTIALIASED version and try Adding sound effects in Premiere