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Three Dimensional Computer Graphics

Many computer models involve three-dimensional (3D) computer graphics. If an object is three dimensional then it has a certain height, width and depth: in other words it should look realistic.

Computer graphics are used in computer games; engineering & design; TV & cinema; and in any situation where you want the computer to generate a picture that looks like the real world.

Computer graphics can be used to model the appearence of an object before it has been built. Each triangle represents a different flat surface on the object.

A cube is made of flat surfaces so it would be made of only a few triangles; a ball, on the other hand, would be made up of many thousands of little triangles.

Most computer graphic models are stored in the computer as a mesh of connected triangles. The skeleton of triangles can be moved, rotated and stretched easily using straightforward maths.

Once the mesh of triangles has been manipulated to the correct positions (or transformed) the individual triangles can be coloured in (or rendered).

There are many different ways in which the triangles can be coloured. One simple way is for the computer to calculate how much light would bounce off each triangle and reach your eyes. The shade of each triangle would then be worked out by the computer.

Rendering three-dimensional computer graphics involves a lot of calculations.

The two pictures on this page are examples of vector and bitmap graphics. A picture that is made of points joined together by lines to form a mesh or lattice is an example of vector graphics. This type of graphics is very useful for transforming 3D objects quickly.

Bitmap graphics take up a lot more storage space but they are much better at showing colours and shades.

 

Use the text to answer these questions
(the answers must be exactly correct!)

  1. A 3D object has width, height and what else ?
  2. The point of 3D computer graphics is to make the picture look, what?
  3. What shape is often used to represent a flat surface ?
  4. The model is stored as a lattice of triangles, what's another name for lattice ?
  5. If you manipulate the object into its correct position it has been, what ?
  6. Once the triangles have been coloured in they are said to have been, what ?
  7. The computer calculates what bouncing off the triangle surface ?
  8. What property of each triangle is then worked out by the computer ?
  9. A lattice of points joined by lines is an example of what type of graphics ?
  10. Bitmap graphics are good at showing shades and what else ?

You scored out of 10 on that test

Try these internet sites for more examples of 3D modelling:
Image created using POV-Ray
© 2003 J Ewart | S Peters