How do I design certain pipes to have different design constraints from those specified in the Default Design Constraints?
In this wiki the slope design constraint is considered. The same principal will apply for velocity and cover constraints as well. This will also assume that you want to change slope design constraint of pipes connected by catch basins & keep default design constraints for pipes connected by manholes.
1) Constraint based design works for the SewerCAD or StormCAD solvers. If you have SewerGEMS or CivilStorm, open your calculation options (Analysis > Calculation Options) then change the "Active Numerical Solver" to the 'GVF - Convex (SewerCAD)' or 'GVF-Rational (StormCAD)'. Also change the property for the "Calculation Type" to 'Design'.
2) Create a selection set for whichever pipes you want to have that given slope. You can find directions for how to create a selection set from this wiki link:
3) Open the conduit FlexTable based on the selection set you just created. This wiki entry located here describes how to do this using option 2.
4) Use the edit button at the top of the FlexTable to add a these columns to it: Specify Local Pipe Constraints?, Slope (Minimum), Slope (Maximum), and Design Conduit? If you are changing velocity and cover constraints, add these columns: Velocity (Minimum), Velocity (Maximum) & Cover (Minimum), and Cover (Maximum).
5) Use the directions in the wiki referenced in step 3 above to globally edit the "Specify Local Pipe Constraints?" column so that it is set to 'True' (i.e., so the checkbox in the Global Edit dialog has a checkmark in it). After you do this, also globally edit the Slope (Minimum) and Slope (Maximum) fields to the values that you would like. This sets up this selection set of conduits so that you use local pipe constraints for design. In the next step you are going to set up the design constraints for the rest of your system.
6) Go to Components > Default Design Constraints and set the constraints here that you would like to have for the rest of your conduits. If you need an explanation of what each property does you can use the Help button in the lower right corner for a more detailed explanation.
7) Run the model by either clicking the compute button, going to Analysis > Compute, or hitting F9.