Part-based vs. Path-based Pressure Pipe Networks: Roll in 3D Space
The ability to roll pressure pipe fittings in 3D space has seen a need for clarity for a few releases in Civil 3D. It is one of the hurdles that users find preventing them from making use of pressure pipes for laying out pressure systems. Both methods of laying out pressure pipe networks have pros and cons from each other, but this is one ability/need that seems to be missing from most documentation. As a sidebar, this is a feature that Plant 3D shines in when laying out multi-directional pressure pipe runs.
Note: this write-up is based on the 2025 version of Civil 3D.
Part-Based Networks
In the image shown, a 45-degree bend (selected) is added to end of a pipe run and is illustrated in a 3D model view for clarity. Note the partially hidden rotation grip towards the left. That is what is used to control rolling in space and only shows in a 3D viewpoint.
Once selected, the grip shows the compass control in line with the rotational plane for the fitting.
If the dynamic input setting is enabled, you can enter a value directly to control the roll direction. You can also use the compass “snapping” capability to click on the proper angle.
Once rotated, you can continue the layout as desired, which will automatically revert to laying out in plan.
Path-based Networks:
As with the part-based method, rolling fittings in 3D space involves viewing from a 3D viewpoint. Shown below is a 90-degree bend which needs to be rolled but will be done using the AutoCAD Rotate command. There is no grip editing in this case since they only show when working directly with the pipe run. Therefore, to rotate the part, you must align your UCS to the plan of the end connection.
Therefore, to rotate the part, you must align your UCS to the plane of the end connection.
Once you are in this position, you must enter the Rotate command and select your fitting. Proceed through the command by identifying the center of pipe end or part end as the base point and click, or type, the rotation desired. Here, you can use Polar Tracking to click on a snapped-to angle since there is no compass to follow.
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