I've been very happy with doing our Plumbing isometric diagrams in Revit. I took a spin on how a lego instruction manual is set up to "tie together" several 3D slices of a bathroom group. For example, I had one very large bathroom group that was five 3D views, each an incremental slice across the bathroom. Those views are spread out on the sheet and lined up. Then I use detail lines to show where things connect to each other.
Here's an example of a smaller bathroom group that conveys the idea:
Isometric Diagram in Revit.PNG