This one came through on our support desk the other day. One of our clients, a building services consultancy, needed to modify some of their ductwork design. Specifically, they needed to change the length of a transition piece between 2 duct sizes. The problem occurred when they discovered that the standard components you get out of the box with Revit are not set up to do this. If you try and change the length of 1 transition piece in the run of ductwork, they all update across the project. This is because the parameters that control the length of these components are set up as type parameters. To make things a little more user friendly and give greater control over the ductwork design, we can make a few changes to the standard duct transition families. Have a look at the video below to see how this is done.