Does anyone know what the magic is to make a fire damper or other duct accessories auto size? I mean I use the out of the box ones from revit and the are wonderful hover and place into the ducts. Size correctly, everything. I do every thing the same, in other manufacturers models (who dont autosize and link the duct connections to the duct width/height and drop them in and its like they dont care that you are trying to place them into a duct. What gives? Please help!