Datasheet

22
|
CHAPTER 1 The Basics of auTocaD civil 3D
cr e a t e li n e by an g l e co m m a n d
The Create Line By Angle command prompts you for a turned angle and then a distance
(Figure 1.20). This command is useful when you’re creating linework from angles right (in lieu
of angles left) and distances recorded in a traditional handwritten field book (required by law in
many states).
cr e a t e li n e by de f l e c t i o n co m m a n d
By definition, a deflection angle is the angle turned from the extension of a line from the backsight
extending through an instrument. Although this isn’t the most frequently used surveying tool
in this day of data collectors and GPSs, on some occasions you may need to create this type of
line. When you use the Create Line By Deflection command, the command line and tooltips
prompt you for a deflection angle followed by a distance (Figure 1.21). In some cases, deflection
angles are recorded in the field in lieu of right angles.
cr e a t e li n e by st a t i o n /of f s e t co m m a n d
To use the Create Line By Station/Offset command, you must have a Civil 3D Alignment object
in your drawing. The line created from this command allows you to start and/or end a line on
the basis of a station and offset from an alignment.
You’re prompted to choose the alignment and then input a station and offset value. The line
begins at the station and offset value. On the basis of the tooltips, you might expect the line to
be drawn from the alignment station at offset zero and out to the alignment station at the input
offset. This isn’t the case.
Figure 1.19
The tooltip for the
Create Line by Azi-
muth command
Figure 1.20
The tooltip for the
Create Line By
Angle command
Figure 1.21
The tooltips for
the Create Line
By Deflection
command
016817c01.indd 22 5/24/11 10:17:44 AM