There are a vast number of specific types of three-dimensional (3D) computer graphics that are used in an equally vast number of applications. The most basic type of 3D graphics is used to render single scenes or images, sometimes for advertising or other media and sometimes solely for artistic purposes. More rigorously structured 3D graphics are often used in mathematical and scientific visualizations in which the graphics are the result of equations or compiled data as opposed to objects modeled by designers. Advanced 3D software can be used to create animations for motion pictures, television or other mediums. Other types of 3D graphics include game graphics that often are polygon-limited simulation graphics that result from complex algorithms designed to emulate real-world physics or volume-rendered medical and engineering graphics that are used to virtually explore the interior of a three-dimensional object such as the human body.
Using 3D graphics to render a still scene is done in many fields for various reasons. Aside from artistic motives, some interior design or architectural software renders still scenes for the purpose of realistic visualizations. Marketing companies often use 3D designs in campaigns, because the objects that are rendered are dynamic and can be reused consistently within 3D software without the need for repeated photo shoots. Web designers also sometimes render elements in 3D for a more dramatic or realistic appearance.
There are several uses for 3D graphics that do not create objects or scenes that are recognizable. In mathematics and scientific visualization applications, the graphics that are rendered are often in 3D out of necessity, because the data sets are multidimensional and cannot be easily analyzed in a two-dimensional (2D) graph. Meteorological and topographical data also can fall into this category, although it is not uncommon to map some of this information onto simulated images of the Earth or to render extruded terrain from the data to create a realistic image.
One of the largest professional uses for 3D graphics is animation. Three-dimensional animations can be used for motion pictures, television, web media and educational training. Some high-quality 3D animation requires such intense hardware and time that there are companies known as render farms that do nothing but render 3D images for animators from other companies so they can later be stitched together into a fully featured animation.
Video games use 3D graphics in a way that seems similar to 3D animation but actually is very different. Games that employ graphics in 3D generally must use models that take up as little memory as possible and that render to a screen as quickly as possible to achieve a smooth framerate, which is directly the opposite of how most 3D media animations are created. Some games do, however, use high-quality 3D animations that are pre-rendered and played as video clips. Video games and 3D virtual reality graphics can overlap, mostly because a 3D virtual environment in some instances can arguably be considered the same as a video game but without any descriptive game logic applied to the viewer’s actions.
One of the largest uses for 3D graphics is in medical imaging. The graphics are used to implement volume rendering, in which techniques such as magnetic resonance imaging (MRI) are used to take very thin 2D pictures of the body along a given axis. All of these 2D images are then combined, creating a 3D model of a real human body that can be manipulated and explored completely within a computer.