CGI Animation : Definition and Techniques
By Parul Solanki
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.
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