Computer Generated Imagery

Computer-Generated Imagery (CGI) is the application of computer graphics to create or modify visual content. It is widely used in films, television, video games, and architecture to produce both static and dynamic 2D or 3D images. CGI enables the creation of characters, environments, and special effects that are either too expensive, too dangerous, or too physically impossible to film in real life

CGI is fundamentally a post-production digital process. Instead of capturing tangible objects (practical effects) on set, creators build digital assets from wireframes to final renders. These computer-generated elements are then integrated with live-action footage using compositing techniques like green screens.

How CGI is Created

The process of creating high-quality CGI relies on specific tools and methodologies: 

  • Modelling: Artists use software such as Blender or Autodesk Maya to create digital skeletons or meshes, which form the basic shapes of characters or objects.
  • Texturing & Lighting: The digital models are wrapped in textures (e.g., skin, metal, cloth) and lit using virtual light sources that mimic real-world studio lighting.
  • Rendering: The software calculates how light reflects, refracts, and casts shadows on these objects, compiling the data into a final high-resolution image.
  • Compositing: The final renders are layered into live-action backgrounds, with colours and blur adjustments to seamlessly blend the digital world with real-life camera footage.

Common Applications

  • Broadcasting: Overlays in sports telecasting (e.g., the yellow “first down” line in American football or distance markers in swimming) use real-time CGI.
  • Visual Effects (VFX): Modifying or inserting digital elements into live-action footage, such as creating alien worlds in Avatar or monsters in Jurassic Park.
  • Animation: Entirely digital feature-length films (e.g., Toy Story, Shrek) rely exclusively on CGI techniques.
  • Architectural & Product Design: Allowing architects to visualise buildings and engineers to simulate industrial products before they are physically constructed.