Computer Graphics: Computer-generated Imagery

Have you seen the latest Ender's game movie? No!? What are you doing reading this post then? In most movies like Ender's game, computer-generated imagery (CGI) is used.  It is an application of Computer Science (commonly referred to 3D graphics) to create special effects in films, television shows, simulators, commercials, etc.  Content is able to be produced without the use of extra props, and expensive set pieces. The real question is how are these special effects done? There are a few steps to incorporate CGI into a film:

1. Modeling
2. Animation
3. Rendering
4. Compositing

The first step is for an artist to create the images the director wants by the use of clay models, photographs, or drawings.  This could be the hybrid human-alien race in the movie Avatar in which actors take the place of them.  

The second step starts when the model is perfected. The animator tells the computer how the model moves.  An example of this could be how the Transformers move or how their face moves when they talk.
The next step is for a renderer (program that contains lighting, texture, shading, and more features) to create images showing the moving 3D models.  The director modifies the lighting and materials, often doing so until it looks perfect. 

Lastly, the CG images are combined with the live-action part using compositing software.