3D computer graphics

# 3D computer graphics

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3D computer graphics (in contrast to 2D computer graphics
2D computer graphics
2D computer graphics is the computer-based generation of digital images—mostly from two-dimensional models and by techniques specific to them...

) 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 2D images. Such images may be stored for viewing later or displayed in real-time.

Despite these differences, 3D computer graphics rely on many of the same algorithm
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...

s as 2D computer vector graphics
Vector graphics
Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon, which are all based on mathematical expressions, to represent images in computer graphics...

in the wire-frame model and 2D computer raster graphics
Raster graphics
In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...

in the final rendered display. In computer graphics software, the distinction between 2D and 3D is occasionally blurred; 2D applications may use 3D techniques to achieve effects such as lighting
Lighting
Lighting or illumination is the deliberate application of light to achieve some practical or aesthetic effect. Lighting includes the use of both artificial light sources such as lamps and light fixtures, as well as natural illumination by capturing daylight...

, and 3D may use 2D rendering techniques.

3D computer graphics are often referred to as 3D models
3D modeling
In 3D computer graphics, 3D modeling is the process of developing a mathematical representation of any three-dimensional surface of object via specialized software. The product is called a 3D model...

. Apart from the rendered graphic, the model is contained within the graphical data file. However, there are differences. A 3D model is the mathematical
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

representation of any three-dimensional
Three-dimensional space
Three-dimensional space is a geometric 3-parameters model of the physical universe in which we live. These three dimensions are commonly called length, width, and depth , although any three directions can be chosen, provided that they do not lie in the same plane.In physics and mathematics, a...

object. A model is not technically a graphic until it is displayed. Due to 3D printing
3D printing
3D printing is a form of additive manufacturing technology where a three dimensional object is created by laying down successive layers of material. 3D printers are generally faster, more affordable, and easier to use than other additive manufacturing technologies. However, the term 3D printing is...

, 3D models are not confined to virtual space. A model can be displayed visually as a two-dimensional image through a process called 3D rendering
3D rendering
3D rendering is the 3D computer graphics process of automatically converting 3D wire frame models into 2D images with 3D photorealistic effects on a computer.-Rendering methods:...

,
or used in non-graphical computer simulation
Computer simulation
A computer simulation, a computer model, or a computational model is a computer program, or network of computers, that attempts to simulate an abstract model of a particular system...

s and calculations.

## History

William Fetter
William Fetter
William Fetter was an American computer graphics art director. In 1964, while working for Boeing, he made the first computer model of a human body . He coined the term Computer Graphics in 1960, to describe his work at Boeing....

was credited with coining the term computer graphics in 1961 to describe his work at Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...

. One of the first displays of computer animation was Futureworld
Futureworld
Futureworld is a 1976 sequel to the 1973 science fiction film Westworld. It was written by George Schenk and Mayo Simon, and directed by Richard T. Heffron. The cast included Peter Fonda, Blythe Danner, and Arthur Hill. There is also a cameo appearance by Yul Brynner in a dream sequence...

(1976), which included an animation
Animation
Animation is the rapid display of a sequence of images of 2-D or 3-D artwork or model positions in order to create an illusion of movement. The effect is an optical illusion of motion due to the phenomenon of persistence of vision, and can be created and demonstrated in several ways...

of a human face and hand—produced by Ed Catmull
Edwin Catmull
Dr. Edwin Earl Catmull, Ph.D. is a computer scientist and current president of Walt Disney Animation Studios and Pixar Animation Studios. As a computer scientist, Catmull has contributed to many important developments in computer graphics....

and Fred Parke
Fred Parke
Frederic Ira Parke graduated from the University of Utah with a BS degree in physics in 1965. He was then a graduate student of the University of Utah College of Engineering where he received his MS and PhD in computer science. Parke was the creator of the first CG physically modeled human face...

at the University of Utah
University of Utah
The University of Utah, also known as the U or the U of U, is a public, coeducational research university in Salt Lake City, Utah, United States. The university was established in 1850 as the University of Deseret by the General Assembly of the provisional State of Deseret, making it Utah's oldest...

.

## Overview

The process of creating 3D computer graphics can be sequentially divided into three basic phases: 3D modeling
3D modeling
In 3D computer graphics, 3D modeling is the process of developing a mathematical representation of any three-dimensional surface of object via specialized software. The product is called a 3D model...

which describes the process of forming the shape of an object, layout and animation
Computer animation
Computer animation is the process used for generating animated images by using computer graphics. The more general term computer generated imagery encompasses both static scenes and dynamic images, while computer animation only refers to moving images....

which describes the motion and placement of objects within a scene, and 3D rendering
3D rendering
3D rendering is the 3D computer graphics process of automatically converting 3D wire frame models into 2D images with 3D photorealistic effects on a computer.-Rendering methods:...

which produces an image of an object.

### Modeling

The model describes the process of forming the shape of an object. The two most common sources of 3D models are those originated on the computer by an artist or engineer using some kind of 3D modeling tool, and those scanned into a computer from real-world objects. Models can also be produced procedurally
Procedural modeling
Procedural modeling is an umbrella term for a number of techniques in computer graphics to create 3D models and textures from sets of rules. L-Systems, fractals, and generative modeling are procedural modeling techniques since they apply algorithms for producing scenes...

or via physical simulation. Basically a 3D model is formed from points generally called „vertex“ which are defining the shape and forming „polygons“. A “polygon” is an area formed from at least three vertexes and in this case the polygon takes the name „triangle“. When the polygon is formed from four points „vertex“ it’s called „quad“ and if from more than four it’s called „n-gon“. The overall integrity of the model and ability to use in animation is depending on the structure of the polygons where the optional polygon is „quad“.

### Layout and animation

Before objects are rendered, they must be placed (laid out) within a scene
Scene (fiction)
In fiction, a scene is a unit of drama. A sequel is what follows; an aftermath. Together, scene and sequel provide the building blocks of plot for short stories, novels, and other forms of fiction.-Characteristics of a scene:...

. This is what defines the spatial relationships between objects in a scene including location
Location (geography)
The terms location and place in geography are used to identify a point or an area on the Earth's surface or elsewhere. The term 'location' generally implies a higher degree of can certainty than "place" which often has an ambiguous boundary relying more on human/social attributes of place identity...

and size
Dimension
In physics and mathematics, the dimension of a space or object is informally defined as the minimum number of coordinates needed to specify any point within it. Thus a line has a dimension of one because only one coordinate is needed to specify a point on it...

. Animation refers to the temporal description of an object, i.e., how it moves and deforms over time. Popular methods include keyframing, inverse kinematics
Inverse kinematics
Inverse kinematics is a subdomain of kinematics, which is of particular interest in robotics and computer animation. In contrast to forward kinematics, which calculates the position of a body after a series of motions, inverse kinematics calculates the motions necessary to achieve a desired...

, and motion capture
Motion capture
Motion capture, motion tracking, or mocap are terms used to describe the process of recording movement and translating that movement on to a digital model. It is used in military, entertainment, sports, and medical applications, and for validation of computer vision and robotics...

, though many of these techniques are used in conjunction with each other. As with modeling, physical simulation is another way of specifying motion.

### Rendering

Rendering converts a model into an image either by simulating light transport
Light transport theory
Light transport theory deals with the mathematics behind calculating the energy transfers between media that affect visibility. This article is currently specific to light transport in rendering processes such as global illumination and HDRI....

to get photorealistic images, or by applying some kind of style as in non-photorealistic rendering
Non-photorealistic rendering
Non-Photorealistic rendering is an area of computer graphics that focuses on enabling a wide variety of expressive styles for digital art. In contrast to traditional computer graphics, which has focused on photorealism, NPR is inspired by artistic styles such as painting, drawing, technical...

. 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 3D computer graphics software
3D computer graphics software
3D computer graphics software refers to programs used to create 3D computer-generated imagery. This article covers only some of the software used.-Uses:...

or a 3D graphics API. The process of altering the scene into a suitable form for rendering also involves 3D projection
3D projection
3D projection is any method of mapping three-dimensional points to a two-dimensional plane. As most current methods for displaying graphical data are based on planar two-dimensional media, the use of this type of projection is widespread, especially in computer graphics, engineering and drafting.-...

which allows a three-dimensional image to be viewed in two dimensions.

## Communities

There are a multitude of websites designed to help educate and support 3D 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.

## Distinction from photorealistic 2D graphics

Not all computer graphics that appear 3D are based on a wireframe model. 2D computer graphics with 3D photorealistic effects are often achieved without wireframe modeling and are sometimes indistinguishable in the final form. Some graphic art software includes filters that can be applied to 2D vector graphics or 2D raster graphics on transparent layers. Visual artists may also copy or visualize 3D effects and manually render
Artistic rendering
Rendering in visual art and technical drawing means the process of creating, shading, and texturing of an image, especially a photorealistic one. It can also be used to describe the quality of execution of that process...