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CHAPTER 1 The Basics of auTocaD civil 3D
One common question that surrounds the Object Layers tab is the check box at the lower left:
Immediate And Independent Layer On/Off Control Of Display Components. What the heck
does that mean? Relax—it’s not as complicated as it sounds.
Many objects in Civil 3D are built from underlying components. Take an alignment, for
example. It’s built from tangents, curves, spirals, extension lines, and so on. Each of these com-
ponents can be assigned its own layer—in other words, the lines could be assigned to the LINES
layer, curves to the CURVES layer, and so on. When this check box is selected, the component’s
layer exerts some control. In the example given, if the alignment is assigned to the ALIGN layer
and the box is selected, turning off (not freezing) the LINES layer will make the line compo-
nents of that alignment disappear. Deselect this control, and the LINES layer’s status won’t have
any effect on the visibility of the alignment line components.
Finally, it’s important to note that this layer control determines the object’s parent layer at
creation. Civil 3D objects can be moved to other layers at any time. Changing this setting doesn’t
change any objects already in place in the drawing.
Abbreviations Tab
You could work for years without noticing the Abbreviations tab. The options on this tab allow
you to set the abbreviations Civil 3D uses when labeling items as part of its automated routines.
The prebuilt settings are based on user feedback, and many of them are the same as the settings
from Land Desktop, the last-generation civil engineering product from Autodesk.
Changing an abbreviation is as simple as clicking in the Value field and typing a new one.
Notice that the Alignment Geometry Point Entity Data section has a larger set of values and
some formulas attached. They are more representative of other label styles, and we’ll visit the
label editor in Chapter 19, Styles.
Ambient Settings Tab
The Ambient Settings tab can be daunting at first. The term ambient means “surround” or “sur-
rounding,” and these settings control many of the math, labeling, and display features, as well
Figure 1.6
Changing the Layer
setting for the
Catchment object
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