Plant 3D piping is the bulk of most models, so it is tempting to treat it as the simple part: draw lines between the equipment and you are done. Route, connect, move on. But Plant 3D piping is more than a line. It is a set of spec correct components, the pipe and the fittings […]
Plant 3D piping is the bulk of most models, so it is tempting to treat it as the simple part: draw lines between the equipment and you are done. Route, connect, move on.
But Plant 3D piping is more than a line. It is a set of spec correct components, the pipe and the fittings the software drops in for you, each carrying the data your drawings and reports will need. And on an existing site there is a second catch: the routes on your old isometrics are not necessarily where the pipe actually runs.
Get the spec or the route wrong and the error does not stay on screen. It flows into your isometrics and your bills of materials, so fabrication is built to the wrong information, spools arrive that do not fit, and procurement orders the wrong parts. On a brownfield site, rebuilding the model from the original design isos bakes in a plant that no longer exists.
If you own the site, that is wrong quantities, wrong drawings and an asset record you cannot lean on, all of it costing money to put right. If you engineer the site, you are the one rerouting the clash, redrawing the spool, and explaining why the model did not match the field.
It comes back to your specs. You will rarely have just one. You might run a carbon steel 150lb, a stainless 150lb, a galvanised, and more. We cover building them in their own article, but the point for piping is what they give you once built.
Route with a spec and your Plant 3D piping comes out consistent, correctly sized and carrying the right data. As you go, Autodesk Plant 3D inserts the spec’s fittings for you: the elbow at a bend, the reducer at a size change, the flanges where the spec calls for them. That is the “and fittings” part. You are routing, not placing every component by hand.
Each line carries properties you can read and edit. To and from, so a correctly tagged line tells you what it connects. Status, whether new, existing or demolition, which drives the line colouring set up in the project. Tracing and insulation. Tie in and spool numbers, both of which feed your isometrics, where you can produce full line drawings or individual spools.
These are not just fields for the drawing. They make each line something you can interrogate: find every stainless line, every line marked for demolition, every traced line, in seconds. That is the difference between a picture and a model. And because it is a model, it can be checked against the P&ID, so every line on the diagram is confirmed to exist in 3D at the right size and spec.
For routing new Plant 3D piping the toolkit is deep but fast. You set the nominal bore and spec before you start, both changeable later through the properties. The Compass holds lines to clean 45 and 90 degree orientations. Slopes fall a line for gravity, which the isometric then shows. Cutback elbows handle awkward tie ins, where the bill of materials reads a full elbow while the drawing shows the cutback. Rolled elbows cover piggable or low turbulence lines, setting a bend radius the drawing shows as pipework rather than a fitting. Stub ins let you override the spec’s branch table and tie in directly instead of with a tee. Custom items drop in a one off piece without building it into the spec. And the software will not cut pipe shorter than its nominal bore, which quietly prevents a common mistake. One tip: if a spec uses an unusual joint such as Victaulic, set the joint type first in the project’s Piping Connection Settings. Pipe supports are placed as you route as well, taking their line number automatically, and they have their own article later in this series.
The Compass keeps greenfield clean. Real pipe rarely is. It is worth remembering that a design model and the as built plant are not the same thing. A site may have been built from design isos, but pipe is the thing that gets rerouted most during construction: around obstructions, to suit access, to fit whatever was actually there on the day. So the old isos record the intent, not the plant. For brownfield we trace the real runs from the point cloud, at whatever angles they truly are, so the model, and the isometrics that come off it, match the site as it stands.
This is our work. We build the specs your site runs on and route your Plant 3D piping to them, so your isometrics and bills of materials come out correct and consistent. For existing sites we model your actual pipe runs from the laser scan, not from old drawings, so the model matches the plant rather than the intent. And we make sure every line carries the data, status, insulation, tie ins and tagging, that your drawings, reports and asset records depend on.
If your Plant 3D piping was rebuilt from original isos, it is worth asking whether it matches what was actually installed. More often than not, it does not.
Next in this series: The Breakdown of Plant 3D In line Components.
