VFX Techniques: Crowd Replication with After Effects

Simulate a large crowd using live-action footage of a small group of people, 3D renders, and Photoshop artwork.

VFX Techniques introduces common yet critical visual effects techniques that are used in film and television shows on a regular basis. This installment shows how to simulate a large crowd by combining live-action footage of a small group of people, 3D renders, and Adobe Photoshop artwork—transforming an otherwise empty building into a rapt audience. Author Lee Lanier uses After Effects to set up image sequences, apply motion tracking to match the motion of the original camera, and key green-screen footage. Finally, you'll learn how to make all the elements cohesive with color correction and lighting techniques.

Introduction

• Welcome
• Using the exercise files

1. Getting Started

• The breakdown of the final composition
• Reviewing image sequences
• Setting up the project in After Effects

2. Tracking and Integrating Renders

• Removing camera jitter
• Motion tracking CG renders
• Integrating CG renders
• Adding multiple trackers
• Adding artwork and renders
• Utilizing corner pin tracking
• Looking closer at corner pin tracking
• Creating light effects

3. Working with Greenscreen

• Keying with Keylight
• Motion tracking greenscreen
• Applying tracks to multiple layers
• Solving bad matte edges
• Creating fake reflections and parallax
• Utilizing prerendering and precomps
• Rotoscoping greenscreen
• Employing multiple keyers
• Applying matte tools
• Adding lens blur
• Using Color Range and Matte Choker

4. Color Grading and Rendering

• Balancing the saturation and brightness of elements
• Changing clothing and hair color
• Relighting in the composition
• Finalizing the composite
• Adding audio and rendering
• Looking at the final scene

Conclusion

• Next steps