Loading Networks

How to load a Civil 3D pipe network into HydraStorm for hydraulic analysis.

Network Selector

The dropdown in the toolbar lists all pipe networks in the current drawing. Select a network from the dropdown to load it into HydraStorm.

Re-reading the Drawing

HydraStorm reads a network from the drawing the first time you select it. Re-selecting a network already open in the session does not re-read it — once a pipe or structure changes in Civil 3D, use the Refresh from CAD toolbar button (see below) instead of switching networks back and forth. A brand-new network added to the drawing appears in the Network dropdown after a refresh, which re-reads the drawing’s network list as well.

Refresh from Civil 3D

The Refresh from CAD toolbar button (the ↻ icon just right of the Storm selector) re-reads the active network from Civil 3D and opens a Refresh from Civil 3D dialog showing every difference before any of it reaches your model. Nothing is written or removed until you click Apply Refresh; Cancel leaves the model exactly as it was.

The icon lights up amber with a ⚠ overlay when HydraStorm detects that a pipe or structure was added, erased, or modified in the drawing since it last read the network. This is a prompt, not an automatic refresh — nothing re-reads on its own, and HydraStorm's own Apply-to-C3D writes never light the badge.

The review dialog is organized into sections; a section with nothing to show is hidden:

• Re-created structures — a structure deleted and redrawn in Civil 3D gets a brand-new object handle even at the same location connecting the same pipes. When HydraStorm finds a removed structure and an added one that evidently match, it lists the pair here, checked by default. Re-keying tells the project they're the same structure, so hydrology, basin assignments, HydraLink links, and Auto Design anchors carry over onto the new handle; unchecking treats the pair as a plain removal plus addition.
• Values that differ — your decision — a three-way comparison against the last point HydraStorm and the drawing agreed. If only the drawing changed a property, it's not a decision at all — it's listed under Updated from the drawing instead. If only HydraStorm changed it (an edit made but not yet applied), it's kept silently and stays pending for your next Apply. If both changed, the row is a genuine conflict with a Keep HydraStorm value checkbox, checked by default; uncheck it to take the drawing's value instead and drop the pending HydraStorm edit.
• Updated from the drawing — values that changed in Civil 3D with no local edit to conflict with. These are stated, not asked.
• Removed from the drawing — structures no longer in Civil 3D, with what each one carried named beside it. Basin assignments and HydraLink flow links survive as orphans, reported under Network Issues until re-assigned (or matched by a re-point suggestion below); everything else on the structure — loss type, inlet type, peak flows, and so on — is lost with it.
• Added to the drawing — new structures joining the model. Their part descriptions get loss-type and inlet-type suggestions, same as any newly imported structure — never applied without confirmation.
• HydraLink links to re-point — suggestions — a basin or flow link whose structure is gone can be re-pointed at a structure the drawing just gained, but only when the evidence supports it: the HydraLink element's own drawing coordinate lands near the new structure, or the former structure stood within about 25 ft of it. A name match alone is never enough. Rows are unchecked by default, since a re-point is a new claim about where the water goes — an unchecked row stays orphaned and listed under Network Issues.

A handful of properties always take the drawing's value and are shown as informational rows rather than conflicts, because HydraStorm treats them as facts about the drawing rather than design decisions: pipe length and endpoint locations, structure location, part description, the null-structure flag, material, and reference alignment.

The Same Review at Project Load

Opening a project whose drawing has changed since the file was saved runs the identical Refresh from Civil 3D dialog, with one difference: a saved file carries no record of what HydraStorm and the drawing last agreed on, so every value difference is shown as a conflict rather than sorted into "updated from the drawing" versus "kept pending." The likeliest cause is an edit made in HydraStorm and saved, but never applied to the drawing — Keep HydraStorm value (checked by default) keeps it pending for your next Apply. Cancel abandons the load entirely.

This replaces the older separate prompts for re-created structures, drawing changes, and load conflicts with one dialog. The "wrong drawing" prompt and the network-not-found / drawing-name-mismatch warnings are unrelated checks and still appear on their own.

What Gets Read

When you load a network, HydraStorm reads the following data from Civil 3D:

• Pipe geometry: start/end structures, invert elevations, length, inner diameter/width, and curve geometry (center point and radius) for curved-alignment pipes
• Pipe properties: shape (circular/box), part family, Manning's n
• Structure properties: rim elevation, sump depth, part description
• Alignment assignments — each pipe's reference alignment and its projected station along that alignment, which drives run ordering and CAD table station columns
• Structure locations (coordinates, used for spatial matching in HydraLink mode)

Pipe Crossings

HydraStorm also scans the drawing's other pipe networks — including data-shortcut'd water and sewer lines — for crossings against the active network, capturing each foreign pipe's invert, crown, size, material, and name. This scan runs at network import, at Refresh from CAD, at project load, whenever you choose View > Rescan Crossings, and when you create profile views or save the crossing table. Nothing watches the drawing continuously in between: a synchronized data shortcut, a moved utility, or one added or deleted mid-session won't show up until the next scan. See Profile View for how crossings are displayed.

Network Issues at Load

After a network loads, HydraStorm checks it for connectivity problems, mis-labeled pipes, and several data-integrity conditions (orphaned basin assignments, broken inlet bypass targets, unresolved inlet types, ponds drawn as a single pass-through structure, and more) and surfaces the count on the toolbar's Drawing menu button, and on the Network Issues item inside it. See Main Window for the full list.

Structure Re-Key

Civil 3D assigns a brand-new object handle whenever a structure is deleted and redrawn, even at the same location connecting the same pipes — so a saved project's handle-based links (loss type assignments, sizing anchors, HydraLink links) would otherwise silently stop resolving. The Re-created structures section of the Refresh from Civil 3D dialog is where this is offered, whether you triggered the refresh by hand or it ran automatically at project load; it's only offered when the project and the drawing genuinely match, and never fires when the wrong drawing is open.

Identity Tracking

HydraStorm identifies each pipe and structure by its Civil 3D object handle rather than by name, so renaming a part in the drawing never breaks the link. Your HydraStorm project file (.hsp) stays matched to the correct objects even after saving and reopening the drawing.

Multiple Networks

Each drawing can contain multiple pipe networks. HydraStorm works with one network at a time. To switch networks, select a different network from the dropdown.

Disconnected Sub-Networks

HydraStorm handles pipe networks that contain disconnected branches. Each sub-network is calculated independently and requires its own downstream boundary condition (normal depth, user-specified elevation, or (Dc + D) / 2).

Drawing ↔ Project File Link

A drawing can point at the .hsp project file that goes with it, so opening the drawing auto-loads the matching project without a manual Open Project step. Set this up (or change it) from Project > Link to Project File.... If the linked file can't be found — moved, renamed, or on a network share that isn't reachable — a banner appears above the toolbar with Locate… (point at the file's new location) and Unlink (remove the pointer) actions; the session still works from the drawing in the meantime. Unlink from Drawing in the Project menu removes the pointer directly.