1. Space and its Dimensions

What is meant by  ‘3D’?

The abbreviation ‘3D’ stands for ‘three-dimensional’. This can be very simply illustrated by the movements of the red ball in the following images.

3 dimensions


  1. When a ball is only able move to the right and the left (in one line), this ball is located in a one-dimensional space.


  2. If the ball has the possibility to move not only to the left and to the right, but also backwards and forwards, this ball is located in a two-dimensional space.


  3. A three-dimensional space is, for example, a closed box where the ball has the possibility to move:
    • to the left and to the right
    • backwards and forwards
    • upwards and downwards

The three dimensions are:
  • to the left and to the right (width)
  • backwards and forwards (depth)
  • upwards and downwards (height)

These three dimensions make it possible to observe this 3D world out of different points of view: the front, the back, the sides, the bottom and the top.