Cartesian Co-ordinate System

3D software uses the Cartesian Co-ordinate System to create the illusion of working in three-dimensional space on a 2-dimentional environment. 

French mathematician Rene Descartes first developed the Cartesian coordinate system in 1637 to create this illusion of working in 3-dimentational space. He did this in an attempt to merge algebra and Euclidean geometry.  

The two 2 axes that commonly define the 2-dimentational Cartesian system are the Y and X axis. The point where the XY axes meet is known as the Origin. 

The importance of the Z axis is that it measures the depth of an object and is the axes that enable us to locate any point in 3-dimentational space.  

The correct way of using the X,Y,Z is to right them in that order for example 

59 units along the negative x-axis

100 units along the positive y-axis

50 units along the negative z-axis  

Would be written as (-59,100,-50) 

Most 3D software applications present us with multiple viewports of the co-ordinate system at the same time. These are the ‘Top Viewport’ showing you the X,Y co-ordinates, the ‘Front Viewport’ showing you the X,Z co-ordinates and the ‘Left Viewport’ showing you the Y,Z co-ordinates. These are known as the orthographic Viewports because they only display 2 axes at the same time. Then you have the ‘Perspective Viewport’ showing you the X,Y,Z co-ordinates giving you a more 3-dimentional view. 

The importance of these viewports are that with the understanding of the Cartesian Co-ordinates System you can define and manipulate geometric shapes and with the Viewports this makes it easier to see the geometric shape.