1. DEE 3061 – COMPUTER AIDED DESIGN (CAD)
CHAPTER 1

2. Absolute coordinate system can be used when you know the exact X and Y values of the point you want to place in the drawing window.
The absolute coordinate’s method uses the coordinate system to locate points in the drawing window.
All points are measured from the origin (0,0).
ABSOLUTE COORDINATE

3. EXAMPLE Click line Specify 1st point : 0,0 enter
Specify next point :60,0 enter
Specify next point :60,40 enter
Specify next point :0,40 enter
Specify next point :0,0 enter
EXAMPLE

4. EXERCISE Draw using absolute coordinate. click line 0,0 10,0 10,5 25,5
25,20
45,20
45,60
30,60
30,30
0,30

5. A relative Cartesian coordinate is entered as the X and Y distance from the last point specified.
Use relative X,Y coordinate when you know the position.
From the 1st point specified, precede the next coordinate with symbol.
RELATIVE COORDINATE

6. EXAMPLE Click line Specify 1st point : 80,20 enter
Specify next point enter
Specify next point enter
Specify next point enter
Specify next point enter
EXAMPLE

7. EXERCISE Draw using relative Cartesian coordinate.
Starting points at 10,10.
EXERCISE

8. Polar coordinate is entered as a relative distance and angle from an absolute coordinate or the last point specified.
To enter a polar coordinate, enter a distance and an angle.
For example: click line (10,15)
POLAR COORDINATE

9. EXAMPLE Click line Specify 1st point : 100,80 enter
Specify next point enter
Specify next point enter
Specify next point enter
Specify next point : enter
EXAMPLE

10. EXERCISE
Draw using polar coordinate.
Starting points at 10,5

11. Polar coordinate Relative coordinate @10,0 @0,5 @15,0 @0,15 @20,0
Click line, click anywhere
@10<0
@5<90
@15<0
@15<90
@20<0
@40<90
@15<180
@30<270
@30<180
Click line, click anywhere
@10,0
@0,5
@15,0
@0,15
@20,0
@0,40
@-15,0
@0,-30
@-30,0