Utility networks
Dry and wet infrastructure — water, sewer, storm, gas, electric, telecom — modelled as a network of structures (manholes, chambers, valves) joined by pipes, with a built-in hydraulic solver behind it.
What a network is
Unlike an alignment, a utility system is a graph: structures are the nodes, pipes are the edges, all held inside one network object in the Object Browser. Each network has a discipline (its colour and behaviour) that decides whether it is pressurised (water, fire) or gravity (foul sewer, storm).
Create one from Utilities ▸ Create Network…. Like Civil 3D's Network Layout Tools, the dialog lets you pick the discipline, the structure and pipe part families from the catalog (these seed the network's Parts List defaults), a reference surface for rim levels, and — for the along-alignment method — the alignment to lay the run beside. Then either draw it freehand in Plan or lay it along the chosen alignment.
Editing a network
Select a network, then use the Utilities ▸ Modify commands. Every edit is undoable.
| Command | What it does |
|---|---|
| Add Structure | Click in Plan to drop a structure into the selected network; it auto-connects to the nearest one with a pipe. |
| Connect Pipe | Click two structures to join them with a pipe. |
| Draw Catchment | Draw a service-area polygon; it drains to the nearest structure (used by the storm solver). |
| Delete Part | Removes the selected pipe / structure / catchment (also the Del key in the viewport). |
| Split at Pipe | Cuts the selected pipe; if that splits the graph, the cut-off side becomes a new network. |
| Merge Networks | Folds one network's structures and pipes into another. |
Pick any pipe or structure to edit its properties — name, diameter, slope, rim / invert, and (Civil-3D style) a pipe's own start / end invert for a drop across the structure. You can also move structures by dragging their grips in Plan, or their rim / invert in the Profile view.
Parts List, rules & naming
- Parts List (Utilities ▸ Design) — a catalog surface: the network's default pipe / structure family, a per-member assignment grid, the design rules and the naming templates in one dialog. Parts come from the Part Builder definitions, so sizes and wall thickness are real, not hardcoded.
- Design Settings… (Utilities ▸ Design) — a tabbed editor for
everything that governs the network, applied as one undoable step:
- Design Rules — min cover, min/max slope, max pipe length, min/max velocity, structure drop.
- Hydraulics — source structure, supply head, default demand / inflow, the pressurised headloss formula (Hazen-Williams / Darcy-Weisbach / Chézy-Manning — drives the EPANET solve), simulation duration, routing step, design rainfall.
- Friction — a per-pipe roughness override table. Leave it at
0to use the material default, or type your own value to override it. The column adapts to the discipline: Manning's n for gravity networks, Hazen-Williams C for pressurised ones — exactly the number the EPANET / SWMM solve uses. - Naming & Parts — structure / pipe name templates and the default catalog families.
- Design rules — Validate Design Rules reports every breach (including connectivity problems — dangling / duplicate / isolated parts) to the Event Viewer; Apply Design Rules lowers inverts so a gravity run meets min slope and cover.
- Naming templates — auto-label structures / pipes with tokens
<KIND>,<#>,<NET>. - Network Quantities — a take-off: pipe length by size and material, structure counts by kind, and an estimated trench excavation volume.
Individual friction overrides are also editable one at a time: pick a pipe and set its Friction (0=material) field in Properties.
Material Library (Utilities ▸ Design) — a project-wide table of
pipe materials and their roughness for every headloss formula
(Hazen-Williams C, Darcy ε in mm, Manning n). This replaces the old
hard-coded values: pick a material on a pipe and the solve reads its roughness
from here. Edits are saved beside the program (materials.txt), so
they survive a restart. Re-run the analysis after editing to apply.
Hydraulic analysis
Two industry-standard engines are built in and run inside the program: EPANET for pressurised networks and SWMM for gravity storm / sewer. There is nothing to install and no file to hand off — you just run the analysis and the results become part of the model.
Setting it up
Select the network and edit its Analysis settings in Properties:
| Setting | Meaning |
|---|---|
| Supply head | EPANET: the source reservoir head above the highest structure. |
| Default demand / inflow | The loading applied at each node when it has no value of its own. |
| Per-structure demand | Override the loading at one structure (Properties of that structure). |
| Design rainfall | SWMM: a storm intensity (mm/hr) that drives runoff from the catchments. |
| Catchment area / imperviousness | A structure's contributing area, or a drawn catchment polygon, generates rainfall-runoff to that node. |
| Duration / routing step | SWMM simulation length and time step. |
A pipe can also be a pump or a valve (PRV / FCV / TCV): set its Link type and a setting (pump kW or valve setting) in the pipe's Properties — the pressurised solve emits the matching element.
Running it
Utilities ▸ Design ▸ Run Analysis picks the right engine for the selected network's discipline (or runs every network), solves, and stores the result. The numbers also go to the Event Viewer.
Refresh Stale Results re-solves only the networks whose results an edit has made out of date, leaving everything else (and never-analysed networks) untouched — a quick way to bring the model back in sync after a round of edits.
Reading the results
- Properties — every pipe and structure gains an Analysis (last run) group: pressure / head / depth / surcharge for structures, flow / velocity / head loss / Froude / capacity for pipes. The network itself shows which engine and headloss formula produced the result, the continuity error, and a status (up to date / out of date / not run).
- Plan — pipes are tinted by a velocity / %-full colour ramp.
- 3D — a gravity pipe with a result turns to a glassy shell with a blue water body filled to the computed depth (red when surcharged), so you can see how full each run is at a glance.
- Profile — the long-section shows the hydraulic grade line (HGL).
- Hydrograph dock — pick a pipe or structure to plot its time series (flow, depth or pressure). The slider scrubs the whole Plan and Profile back through time so you can watch the storm propagate.
Editing the network marks its result stale (the Hydrograph says so) until you re-run — the displayed numbers are never silently out of date.
EPANET and SWMM are the US-EPA open-source engines, embedded under their permissive licenses; yucad3d drives them through their toolkit APIs.