February 28, 2021

AMEP: Plumbing Line "Label" with a Leader

A question came up the other day, concerning Plumbing Lines and the "Label Curves" that AutoCAD MEP provides to label those Plumbing Lines. The request was to be able to be able to label a short Plumbing Line - one shorter than the label itself - by offsetting the label and connecting the label back to the Plumbing Line with a leader.

The results of some quick research suggested that Label Curves do not have a leader option, when offset from the Plumbing Line that they are labeling. I am not sure if there is some inherent limitation here, or it just was never part of the specification for the object. They certainly have many useful features, like masking the Pluming Line, if desired, and repeating at a specified distance or a specified number of times - but no leader.

It occurred to me that, for the stated case of a short Plumbing Line, that the masking and repeating features were not necessary, and that a Schedule Tag, which can have an integral leader, could be created that looks just like the Label Curve, if the data displayed by the Label Curve was available in Property Data. It turns out that, at least for the Standard - Pipe With System Label Label Style, which shows the Object Props. and Abbr. System Name, Plumbing Lines have corresponding Automatic Property sources: Nominal Size and Abbreviation. I was able to create a Property Set Definition that applies to Plumbing Lines and includes three properties:
  • Abbreviation, created from the Abbreviation automatic property source. The Case - Upper Property Data Format was applied to this property.
  • NominalSize, created from the Nominal Size automatic property source. Since I was working in imperial units (it is one of my habits), I applied the Number - Fractional Property Data Format to this property.
  • LineLabel, a formula property, creates the string that is to be displayed in the Schedule Tag. It is a simple concatenation of the text equivalent of the NominalSize property, an inches symbol [via Chr(034)], a space and the Abbreviation property. The Standard Property Data Format was applied to this property.

A Schedule Tag can then be created to display the value in the LineLabel property, a Schedule Tag tool can be created for that Schedule Tag, the tool properties can be edited to include a leader and then the tool can be used to place a tag with a leader. The result can be seen in the image below, where the short Plumbing Line segment has both an offset Label Curve and a Schedule Tag with a leader, so you can compare the two.

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