11. Profile

A long-section between two nodes: ground, conduit inverts and crowns, node shafts, the HGL at the animated instant, and the maximum-HGL envelope of the run. It answers the question the map cannot: where does the water surface sit against the pipe and the ground along this path?

11.1 Choosing a path

Three ways:

Select exactly two nodes and choose View → Profile from Selection.
View → Pick Profile Path…, then click the start node and the end node on the map (Esc cancels).
Right-click a node → Profile from Here…, then click the end node.

The From and To dropdowns in the view's strip change the path without going back to the map; Swap reverses it. The path between the two nodes is found through the model's links, in either direction, so a profile can run against the flow; it is drawn from the first node station 0. If no chain of links joins the two nodes the view says so.

11.2 What is drawn, and where the elevations come from

The geometry comes from the model file the engine ran, reduced to inverts, crowns, rims, offsets and lengths, by the engine's own rules rather than the drawing's convenience:

A link end's invert is the node invert plus the link's offset. With LINK_OFFSETS ELEVATION the offset column is an absolute elevation and is converted to a depth above the node invert, never below it.
A conduit's crown is its invert plus the cross-section's rise (Geom1 for the standard closed shapes).
A node whose MaxDepth is zero or absent takes its rim from the highest crown among the links that connect to it, which is what the engine does when it validates a junction (UM §3.3). Otherwise rim = invert + MaxDepth.
Stations accumulate conduit Length. Pumps, orifices, weirs and outlets have no length and are given a short nominal span so the plot can show them without stacking two nodes on one station.
The ground line joins the rims.

A drop structure therefore shows as a step in the invert at the node, and the shaft runs from the node invert to the rim.

11.3 The HGL

Two lines:

HGL — each node's invert plus its reported Depth at the reporting period on the Time slider, joined node to node. The slider is shared with the Results map, so scrubbing time moves both.
Max HGL (checkbox) — each node's invert plus its maximum depth over the whole run, read from the .out. The engine reports at REPORT_STEP, so the animated line is a set of snapshots and can miss the true peak between steps; the envelope is the maximum of those snapshots at every node. Where it reaches the rim the node was surcharged to the surface — flooding if ALLOW_PONDING is off, ponding if it is on (§16.4).

The elevation shown is the node's own invert plus depth, which is what the engine reports as the node's head when the two agree; if you have edited a node's invert since the run, the profile still shows the geometry the engine ran (see §11.5).

The HGL is drawn between node heads only; no attempt is made to draw a water surface inside a conduit between nodes, because the .out does not carry one (it carries the link's depth at its midpoint, which is a different thing).

11.4 Controls and export

V. exag. — vertical exaggeration; the axis label states it.
Export PNG — the view as drawn.
Export CSV — the station table: one row per node with node, kind, station, invert, rim, hgl, max_hgl, link_in, link_in_invert, link_in_crown, link_out, link_out_invert, link_out_crown, in feet or metres by FLOW_UNITS.

The same station table is a block of the Model Report (§2.10).

11.5 Which file the profile reads

The geometry is read from the model file the engine ran — the file on disk at the path of the last run — not from the document you are editing. Two consequences:

Before the first run of a session the profile has nothing to draw; run the model (or Compare Engines) first.
Edits made after a run do not appear in the profile until you run again. The map and the sheet show the edited document; the profile shows what the engine saw.

The first path offered is the model's first node to its first outfall, so the view is never empty once a run exists.