LESSON - 3:
3.1 Detail on Line:
In the previous lesson, you have learnt how to draw a line. But still problem can arise regarding placing a line at a certain direction. So clear your conception.
Look at the two pictures:
Here, you want to draw a line at 45 degree angle with the horizontal line at the upper side. But when you give the command for 450, the line goes downward. Why?
Because, If you keep the starting point fixed and rotate the base line, it goes clockwise at the upper side and counterclockwise at the downward side. As a result, if you give input of 450 angled line, it goes downward making 450 with the base line counterclockwise.
Now , Imagine a line at the right side of the point (the dotted green line). 
Give line command and hold your cursor above the green line - as you want to draw a line above it at 45 degree angle. Now give input for 45 degree.
This time the line stays at the desired side. Because that side is the counterclockwise side of the imagined line.
But this line is not actually drawn there. So why didn’t the line go downward?
Because AutoCAD considers the line (to measure angle with respect to) towards which you hold your cursor, even if it is not drawn on the paper; And of course only the horizontal line.
Watch video tutorial on the three exercises given in the previous lesson. Please watch carefully the input values.
Exercise-1
Exercise-2
Exercise-3
