Graphics Programs Reference
In-Depth Information
The parts of an assembly are called
subassemblies
. They are dynamically
linked to one another and therefore have the potential to affect one another.
For example, if a curb subassembly is located at the edge of a lane subassem-
bly, the curb subassembly will automatically move outward if the lane width
is increased.
understanding Assembly insertions
To create a corridor, Civil 3D inserts instances of an assembly along a 3D
chain at regular intervals. These assembly insertions can be thought of as the
ribs of the 3D model, providing shape to the road one assembly at a time (see
Figure 9.3).
FiGuRE 9.3
Assemblies inserted at intervals along
a 3D chain
Because the assembly insertions are dynamically linked to the 3D chain, any
change to the alignment or profile will prompt a change in the corridor. The
assembly insertions are also dynamically linked to the assembly itself, so any
change to the assembly will also prompt an update to the corridor.
understanding Corridor Feature lines
To provide a framework in the longitudinal direction, Civil 3D draws feature lines
from assembly to assembly (see Figure 9.4). The feature lines employ a coding
system to determine which points they are drawn through each time they cross
an assembly.
The feature lines are linked to the assembly insertions, which are linked to the
3D chain, and so on. I'll stop calling out relationships specifically and cover it all
by saying that everything within a corridor is essentially related.
