Sewer long section to DXF — step by step

The long section of a sewer is the drawing that eats a disproportionate amount of project time for its size. The route is two days of work; the profile itself — invert levels, gradients, stationing, drop connections, annotations — can swallow another half day of fiddling in CAD and Excel. Below is a concrete path: from coordinates to a deliverable DXF, with no layer cleanup after export.

What you need as input

Coordinates of the route's characteristic points — manholes, bends, crossing locations — are enough. The format is flexible:

• X, Y, Z (existing ground level) — full variant,
• X, Y — when ground levels come from another source or you accept a default,
• any separator (comma, semicolon, tab, space) — auto-detected,
• paste from the clipboard straight out of Excel or a CAD coordinate table.

Any metric coordinate system works (UTM, national grids such as PL-2000 or OSGB36, etc.). Large coordinate values (hundreds of thousands) are automatically shifted by an offset toward zero so the drawing stays stable in CAD — no manual recalculation needed.

Step 1 — Import the route

Paste or load the points. The main run is built from consecutive points; branches attach as separate paths to a node. Set the network type to "gravity sewer" here — default depths, diameters and material become sensible immediately, and the profile is computed against the channel invert rather than the axis.

Step 2 — Levels, gradients, depths

This is the actual design work. For a gravity sewer the key quantities are:

• invert level at each manhole (derived from the gradient or entered directly),
• gradient of a reach in ‰ or % — computed automatically from levels or typed in, with the other value recalculated instantly,
• cover depth — controlled along the whole route,
• drop connection in a manhole — when the difference between inlet and outlet invert requires a step.

Minimum and maximum gradients depend on diameter and the applicable standard — see our guide on gravity sewer gradients for the design rules.

Step 3 — Objects and crossings

You place objects on the profile and plan view: manholes, chambers, road crossings, casing pipes, conflicts with other utilities. Crossings with foreign networks are marked automatically — on the plan and at the right place on the profile, with the conflict level.

Step 4 — Profile table

Below the drawing you configure the table rows the way your practice and reviewer require: existing and designed ground level, invert level, depth, gradients and lengths, diameter and material, stationing, angles, drop. You switch on only what belongs on the sheet. Not sure how the table is read? See how to read a long section.

Step 5 — DXF export

The most important moment — and the one where time is usually lost after a "finished" drawing. The export gives you:

• dual scale — separate horizontal and vertical (e.g. 1:500 / 1:100),
• clean, named layers with an industry prefix (P_KAN_TRASA, P_KAN_RZEDNE, P_KAN_OPISY),
• editable MText, not exploded geometry — fix annotations in CAD without rebuilding them,
• a correct offset, so the drawing opens where it should.

The AC1018+ file opens in AutoCAD, BricsCAD, ZWCAD or GstarCAD. The point is a DXF that is deliverable immediately, not one that needs half an hour of tidying before handover.

What you gain

What used to take hours of manual drafting and Excel recalculation becomes a few minutes and a few deliberate design decisions. No install, no dongle, in the browser — the result plugs into your existing CAD workflow without replacing anything.

Try it free — 7 days, no card required.