Dept. of Subtle - Sloping Pipe Creates New Pipe

I guess I've never paid close enough attention. When you use the Slope tool in Revit MEP the resulting sloped pipe is really new pipe. Revit recalculates what is necessary to create the slope and reassembles new pipe into the configuration.

I realized this when I was discussing a few options for displaying vent piping differently from the sanitary piping. One technique is to just use the Comment parameter (or some other custom one) to add a "vent" comment. A filter is used to isolate pipes, fittings and accessories that contain the criteria "vent". Pretty straight forward unless you decide to slope the pipe afterward. The sloped pipe loses the comment because it is new pipe and the code that rebuilds the pipe doesn't capture the Comment parameter value. I've posted a VIDEO to help explain this.