In AutoCAD Civil 3D, junction structures have built in resize behaviors that control how far you can move the rim, connected pipes, and sump up and down.
For example, if you move the top-most pipe invert up, raising its elevation to the point where it reaches the top of the structure (rim), the rim moves up automatically. This is to ensure that the pipe remains connected to the structure below the vertical pipe clearance area. The resize behavior allows the junction structure to maintain the frame height, cone height, and honor the vertical pipe clearance area, at the top of the structure, with no pipes connecting in to that part of the structure.
If you try to move a connected pipe into the structure’s vertical pipe clearance area, you will notice in your drawing that the top of the structure (rim) automatically moves up.
This is just one example of the resize behavior that is built in to junction structures. Other resize behaviors control how far you can move the junction structure’s rim or sump up and down. These resize behaviors are described in more detail in the following sections:
Before editing junction structures, make sure you understand the following about the resize behavior:
- Elevation changes to the junction structure’s rim, connected pipes, or sump, could occur when the structure is grip edited, or when the referenced surface changes, or when pipe elevations are changed.
- The resize behavior of junction structures is independent of the behavior supplied by part rules. However, part rules can be configured so that they affect the structure resize behavior. For more information, see Part Rules.
- Note that the resize behaviors explained here apply only to junction structures. They do not apply to inlet/outlet structures or null structure types.
- To verify that a structure is categorized as a junction structure, check that the Part_Type property is set to Struct_Junction. This is displayed on the Part Properties tab of the Structure Properties dialog box, in the Part Data section.
Topics in this section
- Junction Structures With Connected Pipes
Moving pipes that are connected to junction structures invokes certain structure resize behaviors.
- Junction Structures With No Connected Pipes
When there are no pipes connected to a junction structure, the rim and vertical pipe clearance take precedence over the sump.