Computer Graphics & Animation - Computer Science

1 ComputerGraphics & AnimationComputer Animation is the use of computers to create animations. There are a fewdifferent ways to make Computer animations. One is 3D Animation . One way to createcomputer animations is to create objects and then render them. This method producesperfect and three dimensional looking animations. Another way to create computeranimation is to use standard Computer painting tools and to paint single frames andcomposite them. These can later be either saved as a movie file or output to last method of making Computer animations is to use transitions and other specialeffects like morphing to modify existing images and Graphics are any types of images created using any kind of Computer .

2 Thereis a vast amount of types of images a Computer can create. Also, there are just as manyways of creating those images. Images created by computers can be very simple, suchas lines and circles, or extremly complex such as fractals and complicated you want to create your own Computer Graphics , no matter how simple or complex,you have to know a few things about computers, Computer Graphics , and how following information should help you get started in the field of computergraphics:Anti-aliasingl Binary systeml Bit depthl Bitmapl Bitmappedgraphicsl Keyframel Modelingl Morphing & Warpingl Meshl Object orientedgraphicsl Computer (1 of 3) [30/05/2001 11:53.]

3 43 PM]Boolean operationsl Contouringl Coordinate Systeml Digitizingl Ditheringl Facel File typesl Fractalsl Hierarchyl Inverse Kinematicsl Onionskinningl Pixell Primitivesl Real time renderingl Renderingl Resolutionl Surface Mappingl Transitionsl Vertexl Member of the Internet Link ExchangeEvolutionGraphics &AnimationToolsApplicationsComputer (2 of 3) [30/05/2001 11:53:43 PM]Companies &AssociationsFilesOther SitesHelp-n-TipsCreated by Krys Cybulski & David ValentineComputer (3 of 3) [30/05/2001 11:53:43 PM]RenderingRendering is the process a Computer uses to create an image from a data file. Most 3 Dgraphics programs are not capable of drawing the whole scene on the run with all thecolors, textures, lights, and shading.

4 Instead, the user handles a mesh which is a roughrepresentation of an objects. When the user is satisfied with the mesh, he then rendersthe MeshA Rendered ImageWire FrameThis isn't really a rendering method, by definition. Most 3D Graphics programsrepresent objects as meshes. What happens in wire frame rendering is, every section ofthe mseh gets colored in with the average color of the texture. This comes in usefullfor special effects, and for quick previews. To take wire frame rendering one stepfurther, some programs do a process called hidden line removal. It is just like normalwire frame rendering, except the parts of the mesh that would not be visible if theGraphics (1 of 6) [30/05/2001 11:54:11 PM]mesh was a solid are not usually takes a long time.

5 The time it takes to render an image depends onthe quality of rendering. There are a couple of different qualities of ShadingThe quickest rendering method. Some programs are able to render flat shaded objectsin real time. When rendering using flat shading, the Computer takes creates an averagecolor for an object and then renders each face with different amounts of black or whiteadded to simulate shading. Objects look flat and unrealistic. No textures are applied inthis (2 of 6) [30/05/2001 11:54:11 PM]Gourad rendering takes flat rendering one step further. The Computer figures outvalues of a color on vertices of a face and then applies a gradient to the face tosimulate shading.

6 This mode is not much slower than flat shading and can also berendered in real time on some of the more powerfull rendering takes rendering yet one more step further. It actualy probes everypixel in the visible area and tries to determine a correct color for it. It takes intoaccount all lights and textures. This is often as good as many low-end programsrender. The results are pretty good, and the time that it takes to render is not (3 of 6) [30/05/2001 11:54:11 PM]Ray TracingThe best rendering quality. It also takes very long, but the results are is rendered, including shadows, lighting, reflections, and transparancies. Italso does another thing that other rendering options don't.

7 It gives light a physicalattribute. For example, a rendering of a pencil in a glass of water would give you thesame diffraction effect that nature does: the pencil will appear broken. When acomputer ray traces an image, it simulates a beam of light going out of every pixel onthe screen. It reflects and deflects the beam of light in a similar fashion nature it takes outcome of all this and puts it on the is a link to a more "in depth" definition of ray tracing at at this site dedicated to ray (4 of 6) [30/05/2001 11:54:11 PM]There is a new method of rendering that was recently developed. It is called does something all the other rendering methods don't do: it figures out therelationship in the scene of all the objects present.

8 For example, in real life, if you takea bright colored ball and put it into a white room, the walls of the room are going toreflect a little bit of color from the ball, making them look a little reddish for is not possible in raytracing, since it does not bounce rays off of matte objects,such as a can compare the above picture to the one of the raytraced object. Allthough this isnot a very good example, you can see that the checkecrboar pattern of the "tri-ball"has a slight effect on the color of the bricks right underneath it. This adds the extrathing to rendered scenes and makes them look extremely produces extremly good results, but unfortunatly, there is a tradeoff:rendering time.

9 Before the Computer even starts rendering, it has to solve a certain"radiosity model" which is the relationship of one object on all the other ones in ascene. Then it can start some more information on radiostiy,try this site out at some sample images of raytracing and radiosity try this image sampler, again are some links to some extra informations as well as in depth explanations ofterms that have to do with rendering:Color TheoryIlluminationColor and LightDiffuse ReflectionSpecular ReflectionGraphics (5 of 6) [30/05/2001 11:54:11 PM]Reflection & TransparencyShading TechniquesBack to &AnimationToolsApplicationsCompanies &AssociationsFilesOther SitesHelp-n-TipsCreated by Krys Cybulski & David ValentineGraphics (6 of 6) [30/05/2001 11:54.]

10 11 PM]TransitionIn Computer Animation , transitions are ways of moving from one picture to another. Asimple transition might be a fade. In a fade, one image fades out while the other onefades in giving an Animation a cool look. Other examples of transitions are wiping,morphing, blending, to &AnimationToolsApplicationsCompanies &AssociationsFilesOther SitesHelp-n-TipsCreated by Krys Cybulski & David ValentineGraphics [30/05/2001 11:54:14 PM]MorphingMorphing is a very cool looking transition. It is also one of the most complicated morph looks as if two images melt into each other with a very fluid motion. Intechnical terms what happens is, two images are distorted and a fade occurs betweenthem.