Duct standards and companies use straight centerlines in 1-line, 2-line, model, and plan displays to accurately represent the location of the intersection of an elbow. Duct designs typically determine the centerline path. Contractors and fabricators use straight centerlines to guarantee accuracy in process duct installations and fabrication drawings.
The centerline display of elbows in AutoCAD MEP 2023 toolset is based on the path and orientation of connectors 1 and 2 on the elbow. The centerline display typically follows the path of the curve and is generated in all orthographic and model views.
The following example shows a straight centerline of elbows on a duct in 2-line display. One elbow is 45 degrees and the other is 90 degrees.
Straight centerline on duct in 2-line display