Set parameter by name wrong values


I have some problems to import parameters values into Revit.
The dynamo script reads my excel file without problem, the list is ok.
But then the value writtent in Revit are completely wrong.
This are the values inserted in Revit (7237.7860 m³/h and 7339.7266m³/h) but in my Excel file the values are 63 and 64.

How am I supposed to fix that?


I dont understand French, but i have an idea that it is a conversion problem between the SI world and the Imperial world. All units inside Revit is imperial units!

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@erfajo so in Revit, air flows are in ft³/hr?

Just converted the air flows in Excel from m³/h to ft³/h.
Dynamo still has the correct value but again, Revit’s are completly wrong.

Have you tried the MEPover node “SetParameterAsProjectUnits”? Because it sounds like a conversion issue between Revit and Dynamo, but I could be mistaken.

Edit: From a quick Google search it seems that the internal unit for air flow is ft³/min (CFM), does that seem more reasonable?

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it is in the transfer between Dynamo and Revit the problem is, and for a European citizen is it completely obscure system the Imperial system. I have absolutely no understanding of why we have to meet this problem over and over again.


@erfajo is right here.
I don’t know why exactly it happens but I’ve just checked how it changed and added a calculation within Dynamo and though it’s not ideal it does work.

SetParameterAsProjectUnits works ok.
This was indeed a unit problem :confused:

I wonder if I am going to convert in Excel or Dynamo or use SetParameterAsProjectUnits


Convert your return value to Revit. Meaning just before setting the “SetParameterByName” node. and it is a good advice @lsmm gave -> see if @T_Pover (MEPover) package solve your problem…

@erfajo I added a code block to do the calculation and it is working fine.
Thanks to all of you !

Just so you know @erfajo Revit was built in the USA a decade ago and the very first version(s) had no metric in it, it was all imperial :slight_smile:
Rebuilding a software to go unitless is… a HUGE task:)

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I am aware that Revit was built in US, but this obscure conversion problems has caused numerous problems, so why on earth isnt this changed decades ago!?.. US has to adapt to the world, not the other way around!


Why are the US still using imperial measure is … another debate. But in the mean time, the US changing the units of measurements wont solve the issue :slight_smile:
So we go with simple conversion :slight_smile:


I think that One day they wil adapt and need to adapt even the US
they are almost alone


but its harder for a large country to adapt then a little country :wink: