Paweł Romaniuk has shared his workflow to take various parameters from a model, run the necessary algorithms and then write the area back to a parameter for use in a Revit schedule. Link to pdf download is below… Thanks Paweł.
UPDATED Download link:
Dynamo_Duct_Fittings_Calculation_V.0.1
Download:
https://www.dropbox.com/s/r1slk1sbo1eo971/Dynamo_Duct_Fittings_Calculation_V.0.1.pdf?dl=0
via
Revit MEP Dynamo – Duct Fittings Calculation | LinkedIn
link doesn’t work.