SciTech

Computer-generated imaging creates entire new worlds

Credit: Courtesy of Karter, via Flickr Creative Commons Credit: Courtesy of Karter, via Flickr Creative Commons

If you’ve seen the trailer for The Jungle Book, the latest reimagining of the classic book, set to be released on April 15, I suggest you watch it again. Keep in mind that the movie was created with just one actor in an empty room. The rest of the movie was filled in by Computer Generated Imagery (CGI). Consider any other animated or partially animated movie, like The Incredibles, Jurassic World, or Avatar. All were created using CGI. While movies are a common example of this technology put to work, the applications of CGI are varied. Video games, virtual reality programs, theme parks, and even research ventures utilize CGI to display things that can’t be visualized otherwise.

This article will focus on three dimensional CGI animation from a cinematic perspective. CGI is an umbrella term that is used to refer to any image created using computer software. One can create both 2-D and 3-D images using this technology. The major difference between the two is that 3-D CGI is used to create an entire world, system, or animation, whereas 2-D CGI works with image manipulation, often overlaying one image with others. 2-D CGI often involves creating several renderings or frame generations of a particular scene or object and then modifying them further to fit the expected outcome.

Maya, SOCK, Blender, and Lightwave are some examples of software that can be used to produce CGI. Most commercial CGI films use a similar process to movies without CGI: For any movie, the first task is to script it. Without having a clear idea of where story is going to go, or what the characters are supposed to do, the movie may turn into a bizarre, incoherent melting pot full of plot holes. After the script is written, the animator creates the “storyboards,” which are basically several simple renderings of the same scene to get an idea of what works and what doesn’t. These storyboards progress into a formal layout, wherein the entire movie is “completed.” At this stage, none of the characters have features, mouths or faces.

Their outlines and movements are the only data that exist at this stage in the process. Sometimes, this is also when the “voicing over” takes place. This sequential arrangement of the chosen scenes from the storyboard can be referred to as the “layout.” It is just the rough draft of the entire movie. Layout is also done because it is much easier to make changes when the piece is unfinished rather than later, when one would have to work excessively on the details of the scene that has to be modified.

After the layout has been approved by the directors and other parties involved in the animation, the details are filled in. The characters are given physical features, hair, and other sophisticated appendages. Hair animation is often left for the end because it is the hardest and most nuanced bit to actually animate. This is also when the lighting of the scenes is adjusted; the characters and objects are given shadows, illumination, and the like. From a production point of view, that is how animation takes place.

From a slightly more technical perspective, the animation process involves a lot more work than one might think. Most motion animation requires some kind of data about how an object moves. This data can be obtained using several different kind of models, one of which is called the articulate model. This model is a type of skeletal system that defines the joints where motion is possible and in what directions. It determines what movements can be made and limits them to certain points of articulation, just like in a regular skeleton.

Another model for collecting movement data is the deformable object, which is often used to animate things that don’t have clear joints. These include clothes, water, and hair. Usually, animation involves using a hybrid model that combines several kinds of models together. Flip-books are representative of the method of keyframing to generate motion. As the name suggests, keyframing involves defining the frames at several instances in time and contracting them into one film. Another method, usually associated with CGI is to use motion-capture. This involves fitting live actors with certain special equipment, which relays movement data to computers to be rendered and animated on the big screen.

Movie-making is an intense process, and recognizing this process and all of the hard work that goes into it can enhance a movie-watching experience.