In the last chapter we have created all free hand drawings. As mentioned before it is necessary to know the coordinates or dimensions to create any engineering drawings. In AutoCAD there are three coordinate input methods: absolute, relative and polar.
3.1 Absolute or Cartesian Co-ordinates Input: When the drawing points are specified Cartesian coordinates the coordinate input is referred to as ‘Absolute’. The user can enter the co-ordinates in positive, negative real numbers, or integers
Syntax: (X,Y): Example: Command: LINE (Return) Start Point: 2,2 Next point: 4,4 Next point: (Return)
3.2 Relative Co-ordinates Input: In Relative co-ordinate input the user has to specify the present co-ordinates in relation to the last co-ordinates selected.
Syntax:(@X,Y): Example: Command: LINE (Return) Start Point: 2,2 Next point: @0,4
3.3 Polar Co-ordinates Input In ‘Polar’ co-ordinates input the user specifies exact dimensions in relation with the required angle. The degrees are always measured in counter clockwise direction in this type of co-ordinates input as shown in the figure below.
Syntax: (@Distance<Angle) Angle Measurement: Example: Command: LINE (Return) Start Point: 2,2 Next point: @8<45