# 3-D GRAPHICAL TECHNOLOGY.

Three-dimensional (3-D)graphics,which appear to have height,width and depth,gives a real quality to objects in computer programs,especially computer games.3-D technology is a modern innovation which gives an experience by adding the appearance of depth.A game programmer can give single objects or an entire virtual world a 3-D appearance.

Creating a 3-D appearance involves that a wireframe is created. A wireframe is a series of lines,curves,and shapes arranged to resemble an object in a 3-D world.3-D wireframes consist of series of polygons.A completed wireframe enables you to identify the shape of the object,although it appears to be hollow.This hollow shape can be transformed into solid shape by adding a surface to the wireframe.Some 3-D graphics are composed of more than one wireframe.When adding a surface,it is important to make the object look as realistic as possible by adding colour,reflectance and texture.The amount of the objects’s surface reflects is termed Refelectance.With the surface added to the wireframe,we then consider how the object will be lit from one or more lightening sources.

3-D graphics could also be created by using a technique called ray-tracing.This involves drawing an imaginary path that rays of light follow as they leave source and then land on an object.The light intensity will be greater on some portions of the objects and lee on other portions.In addition,the object also might cast a shadow once it is lit from a particular angle.When creating a 3-Dworld,one also has to consider the perspective and depth of field.Perspective refers to the differences in how objects appear in relation to one another when they are close to you or farther away.Objects appearing close may seem to be spaced apart.As they move farther away from you,they become closer to one another.A common technique used to calculate which objects appear infront of or behind one another is called the Z-buffer.Depth of field gives the appearance that objects farther from the viewer are are less focused than closer objects.

Anti-aliasing is the final technique in creating a 3-D world.Anti-aliasing makes curved and diagonal lines appear straight.When computers render graphics with curved and diagonal lines,they often appear jagged.Anti-aliasing inserts additional coloured pixels that give the appearance of a smooth edge.All these techniques combined create a realistic graphic. the complex nature of 3-D technology requires more computing power in order to render a graphic in an acceptable period of time .For instance,Computer gamers often have faster processors,several gigabytes of RAM,and one or more video cards containing at least 256 MB of RAM.These video cards also might support DirectX 11 standard,the video card also must support DierectX 11 standard for the video game to work.

Although game programmers spend many hours creating 3-D graphics for programs such as computer games,the results are rewarding when a player faces an experience so realistic that it is difficult to differentiate between the game and reality.