I’m trying to set the following two Built-in parameters via Dynamo for duct pressure loss calculations: Pressure Loss Method → Set to specific coefficient Loss Method Settings → Set a specific K coefficient given as input for each duct fitting I’ve tried some nodes, recently the Set BuiltIn Param…

try as here should run with ironpython 2 or ironpython 3 [Skærmbillede 2025-02-28 160113] loss methods.dyn (28.0 KB)

Hi @gianluca.pilati1 is it something here you are after…seems controlled by a guid [Gs8BQS10Kz]

Yes exactly for the “Loss Method” parameter, same I’d like to do for the “Loss Method Settings”, passing a value (double) as Specific Coefficient for each fitting. Where did you get these GUIds from? Thanks!

Yes exactly like this. Could you share that piece of code? I’ve tried to adapt the til.shviger code a while ago but was having issues with Revit 2024.

yeah sure but first tomorrow, im not at pc before that

Thanks now it works! I still have a problem on the first run on new fittings when no values were set for the Specific Coefficient. Found out that when the field is empty the script doesn’t run. [image] [image] Also I’m thinking a way to re-run the Revit pressure drop overall calc after the mod…

allrihgt not sure i cant do that…seems work fine here…i think…probably i misunderstand, becoarse my duct fitting always have a value with startup…0.0 in settings—specific coefficient and not empty

Yes I think it happens when you have a fitting already connected to a duct system

i guess i have…hmmm here i just open a new clean project, so my schema is clean and still 0.0 in value [Skærmbillede 2025-02-28 173926]

It might be a glitch of Revit systems that cause it? Would it be possible to add an “if” in the code to deal with this without breaking the run?

Set loss method settings for ducts pressure drop via node

Revit

sovitek February 28, 2025, 9:14am 4

something here ? you can the guid just with get parameter…

Revit_ndklFx4XVE

take a look on this one here…Change Duct Loss Coefficient to Another Fitting in ASHRAE Table - #6 by junny

Topic		Replies	Views
Parameter with value in new window - Set parameter value? DesignScript	12	391	September 6, 2023
Change Duct Loss Coefficient to Another Fitting in ASHRAE Table	32	9688	June 10, 2025
Setting Specific Coefficient for each duct fittings Revit	2	725	November 16, 2021
MEP - How to set dialog box values Packages	16	4126	February 21, 2018
Loss Method does not have Specific Loss & Specific Coefficient as options Revit	6	1739	November 18, 2025

Set loss method settings for ducts pressure drop via node

Related topics