In section,
“Designing in 2D Using Alignments,” you used alignments to design the 2D path of a linear feature, in this case a road. In section, “
Designing Vertically Using Profiles,” you designed the vertical path of the road using profiles. When combined, the alignment and profile form a three-dimensional pathway called a
3D chain. The 3D chain serves as the backbone of your design.
3D chains can actually be seen in your drawing, but only if you view the drawing from a 3D perspective, as shown in
Figure 9.1.
 |
| Figure 9.1 The blue lines represent 3D chains formed by combining alignments with profiles to form a three-dimensional pathway. |
Because the 3D chain is dynamically linked to both the alignment and profile, a change to either one will automatically prompt a change to the 3D chain and subsequently update the corridor.
