Hello. I am trying to automate a work-around for the pressure loss coefficients when producing a duct pressure loss report. While trying to build my own elbow families with automatic loss coefficients, I have discovered an issue with the built-in family "Rectangular Medium Radius Bend - Flanged - Standard". A key dimension for calculating the loss coefficient is the ratio between the throat radius and the bending plane's width. In the example images attached the elbow fitting is exactly the same except for its orientation. The parameter "Throat Radius" is driven by a formula using the "Duct Width", which exchanges values with the "Duct Height". This change is also demonstrated by measurement. In Revit's reassignment of the width and height, the throat radius should be driven by the width in the vertical case. This implies also that aspect ratio of the fitting is inconsistent in different orientations.
Does anyone know of a way to enforce consistency in orientations and parameters when building custom fitting families?
