Following is a basic overview of how computer graphics are created and definitions of some the odd terms used in the
graphics business. This should give you a fundamental understanding of the process of creating computer graphics
and also help you converse more freely with your graphics guru on your next project.
How Are Computer Generated Graphics Created?
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Step 1: Object Modeling
The first thing we have to do is to actually create the geometry of whatever scene or object we are trying to build. This
process is referred to as modeling. Every object in the scene is made up of different arrangements of triangular and
rectangular objects called "faces". The following screen shot shows a wireframe view of a simple cylinder.
Various 3D modeling and animation software packages such as 3DS Max, Lightwave, Maya and others too numerous to
count ease the process of building the model by adding tools to simplify the modeling process. In this case, I simply used a
"Cylinder" tool to specify the dimensions of the cylinder, as well as the number of faces that it contains. We obviously don't
want to be creating each face in the scene one by one as there are hundreds of thousands of faces in the typical scene.
Occasionally, however, we run into an object where we do have model it one face at a time.
One thing you've probably noticed is that the top edge of the cylinder looks faceted. We obviously want our cylinder to look
round, so we just increase the number of faces around the cylinder to give it a smoother look. This is always kind of a
balancing act, as the number of faces in the scene or model dictates among other things how much memory our graphics
computers need, and how long it takes to "render" the scene (we'll get to that later). Game developers in particular (like the
developers of the popular games Halo, Call of Duty, etc.) have to really try to minimize the number of faces in the scene so
that the games will run smoothly in real time.
To build complex objects and entire scenes, we just keep on adding, moving, scaling and adjusting the faces in the scene.
Figure 2 shows a finish scene model. This model contains 148,024 faces and is comprised of 198 individual objects. As a
reference of comparison, this is not what we would consider to be a large scene.
Screen shot of a
view of a cylinder
shot of completed
One important step in the modeling process is to group and organize the objects in the scene so that the later steps of
texturing and animating become easier. In Figure 2, all of the faces for each ship have been grouped together so that if we
need to move a ship to a different location in the scene, we don't have to individually select all of the faces that define the
geometry of the ship.
The modeling stage is a fairly lengthy process, but in some instances, computer models of various objects can be purchased
online at relatively low cost and simply added into the scene.