Location: 01 General : 1 Graphic Symbols
A line, with a centerline marker at one or both ends. The line is detectable.
It is superior to a conventional line element since the tags say, "Hey here's a centerline", and an object can be displayed on multiple stories. Same reasoning as the CenterPoint object.
You can use it as a layout element on ! Layout.NP, or you can display it for output by placing it on a note layer. It's sometimes helpful for dimensioning to show centerlines, in which case they should be clearly labeled as such, so here you go.
This object doesn't take the place of the CenterLine Symbol, you still need that to mark dimension ticks. (Did you know? AIA standards say that dimension ticks on centerlines should be drawn as dots rather than slashes. Unfortunately, ArchiCAD doesn't offer this ability.)