3 D Computer Graphics

                       3 D computer graphics

3 D computer graphics (in contrast to 2 D computer graphics) are graphics that use a three-dimensional representation of geometric data (often Cartesian) that is stored in the computer for the purposes of performing calculations and rendering 2 D images. Such images may be stored for viewing later or displayed in real-time.

3 D computer graphics rely on many of the same algorithms as 2 D computer vector graphics in the wire-frame model and 2 D computer raster graphics in the final rendered display. In computer graphics software, the distinction between 2 D and 3 D is occasionally blurred; 2 D applications may use 3 D techniques to achieve effects such as lighting, and 3 D may use 2 D rendering techniques.

3 D computer graphics are often referred to as 3 D models. Apart from the rendered graphic, the model is contained within the graphical data file. However, there are differences: a 3 D model is the mathematical representation of any three-dimensional object. A model is not technically a graphic until it is displayed. A model can be displayed visually as a two-dimensional image through a process called 3 D rendering or used in non-graphical computer simulations and calculations. With 3D printing, 3 D models are similarly rendered into a 3 D physical representation of the model, with limitations to how accurate the rendering can match the virtual model.

Fig. of 3 D Computer Graphic

HISTORY

William Fetter was credited with coining the term computer graphics in 1961 to describe his work at Boeing. One of the first displays of computer animation was Future world (1976), which included an animation of a human face and a hand that had originally appeared in the 1971 experimental short A Computer Animated Hand, created by University of Utah students Edwin Catullus and Fred Parks.

OVERVIEW

• 3 D computer graphics creation falls into three basic phases:
• 3 D modeling – the process of forming a computer model of an object's shape
• Layout and animation – the motion and placement of objects within a scene
• 3 D rendering – the computer calculations that, based on light placement, surface types, and other qualities, generate the image

Modeling

The model describes the process of forming the shape of an object. The two most common sources of 3 D models are those that an artist or engineer originates on the computer with some kind of 3 D modeling tool, and models scanned into a computer from real-world objects. Models can also be produced procedural or via physical simulation. Basically, a 3 D model is formed from points called vertices (or vertexes) that define the shape and form polygons. A polygon is an area formed from at least three vertexes (a triangle). A four-point polygon is called a quad, and a polygon of more than four points is an n-non[citation needed]. The overall integrity of the model and its suitability to use in animation depend on the structure of the polygons.

Layout and animation

Before rendering into an image, objects must be laid out (place) in a scene. This defines spatial relationships between objects, including location and size. Animation refers to the temporal description of an object (i.e., how it moves and deforms over time. Popular methods include key framing, inverse kinematics, and motion capture). These techniques are often used in combination. As with animation, physical simulation also specifies motion.

Rendering

Rendering converts a model into an image either by simulating light transport to get photo-realistic images, or by applying an art style as in non-photo realistic rendering. The two basic operations in realistic rendering are transport (how much light gets from one place to another) and scattering (how surfaces interact with light). This step is usually performed using 3 D computer graphics software or a 3 D graphics API. Altering the scene into a suitable form for rendering also involves 3 D projection, which displays a three-dimensional image in two dimensions.

COMMUNITIES

There are a multitude of websites designed to help educate and support 3 D graphic artists. Some are managed by software developers and content providers, but there are standalone sites as well. These communities allow for members to seek advice, post tutorials, provide product reviews or post examples of their own work.

DIFFERENCES WITH OTHER TYPES OF COMPUTER GRAPHICS

Distinction from photo realistic 2 D graphics

See also: Still life § 21st century

Not all computer graphics that appear 3 D are based on a wire frame model. 2 D computer graphics with 3 D photo realistic effects are often achieved without wire frame modeling and are sometimes indistinguishable in the final form. Some graphic art software includes filters that can be applied to 2 D vector graphics or 2 D raster graphics on transparent layers. Visual artists may also copy or visualize 3 D effects and manually render photo realistic effects without the use of filters.

Pseudo-3 D and true 3 D

Main article: 2.5 D

Some video games use restricted projections of three-dimensional environments, such as isometric graphics or virtual cameras with fixed angles, either as a way to improve performance of the game engine, or for stylistic and game play concerns. Such games are said to use pseudo-3 D graphics. By contrast, games using 3 D computer graphics without such restrictions are said to use true.