The Hatch angle, as the name suggests, is the angle at which the Hatch is made in an area. Let's take the example of the ANSI31 Hatch pattern. By default, the Hatch is aligned to an angle of 45 degrees with respect to the x axis, and if applied in a simple rectangle, it looks like this with the default setting:
Fig 6.14: The ANSI31 Hatch pattern with the default angle of 0 degrees
Now, if you want to rotate the Hatch pattern so that it becomes completely vertical, then you can add a Hatch angle of 45 degrees. The Hatch angle starts from the default angle of the Hatch pattern, so in this case, since the ANSI31 pattern is already ...
