Single line drawings in Revit plumbing plans (Coarse and Medium displays) show the tick marks for fittings by default. Some design firms prefer to not show tick marks for the elbows, tees, and other fittings. Revit has a setting that allows users to adjust the printed size of the tick marks, but this affects all tick marks for all fittings. I see situations where the designer wants to see tick marks for reducers and couplers, but not some other fittings.
Pipe fitting families can have a parameter added that controls the visibility of the tick marks. This allows the user to specify which fittings should show the tick marks and also allows tick mark visibility to be different for different projects.
Each Pipe Fitting family will need to be modified, but we will take a look at one family here.