What is CGI Animation

We have all laughed at the antics of the 'donkey' in the movie Shrek or loved the character of 'Woody' in the Pixar movie, The Toy Story. However not many of us know the behind-the-curtains story of these animation movies. The use of computer generated imagery or CGI animation in movies, television and commercial media, has met with increasing success over the forty years of its development and usage. However, the resounding success of these animated graphics, has also raised some interesting questions related to its techniques, popularity and its significant limitations. But before we can venture into these unanswered territories, let us define CGI and answer the basic question as to what is CGI animation.

CGI Animation: Definition and Techniques

A subset of the broad field of animation, CGI or computer-generated imagery, can be defined as the use of computers for creating moving images. Using certain 3D animation software tools like Maya, 3ds Max or Blender, the first step of CGI animation, involves creating a 'wire frame' or a geometric model of the object. Now, the surface appearance of the object has to be determined. This involves providing color, texture, reflectivity and transparency to the objects in question, with the help of tools known as 'shaders'. The final step in the animation process, involves the computer rendering of the entire scene. This involves the calculation of the color of the pixels in the scene, which determines the shading, texture mapping, reflection, refraction and photo-realistic rendering. This may sound simple, but given the millions of pixels in a high definition scene, providing the realistic animal movements, skin, hair and fur, is still quite a complex task. Not to mention the problems areas of introducing features like liquids, gases and complex surfaces, like the texture of the face and the clothing.

A simpler method of adding movement to the objects, is by duplicating an image, displayed on the computer screen and repeatedly replacing this new image, that is similar to the previous image, but slightly advanced in the time domain. Thus, using persistence of vision, the illusion of smooth movement is provided by drawing the pictures at 12 fps (frames per second). In a computer generated image, this is achieved by changing the values of the segments of the skeletal model over time, making the character move from frame to frame. There are several methods for achieving that realistic motion, such as keyframing to motion capture.

Impact of CGI Animation

Cheaper than most of the other animation methods, like construction of miniatures or the use of actors or other contributors to the project, CGI animation is increasingly being used for producing high quality visual effects and realistic images. The accessibility to the CGI software tools, in the recent years, has enabled individual artists and small production units to come up with content without the use of actors, expensive set pieces, or props. While 2D CGI was first used in 1973, in the movie Westworld, it has been increasingly used over the years, in popular movies like The Jurassic Park and the Star Wars series. It was in the year 1995, that the first fully computer-generated feature film, Toy Story was released.

The Future of CGI Animation

Technological change is an inevitable part of life, and therein lies the uncertain future of CGI animation. Although people have increasingly taken to the animated bugs, monsters and animals, it is the creation of a photorealistic animation of humans, that remains out of reach for CGI animators. To replicate the complex human emotions and movements as a 3D animation, remains the goal for all animators. However, complete human realism, where there is no distinguishing between a particular movie sequence that is computer-generated or created using real actors in front of movie cameras, seems an unachievable dream. However with the rapid development of the personal computers, that has reduced their rendering time quite significantly, and the images having become more realistic, CGI animation is here to stay, it seems.