CFM and Units, something is awry

Hello All,

I’m working on a script that will go through my project and size air terminals based on given ranges that I input and change their families to different types accordingly…in the process of constructing that script, I’ve come across an interesting issue with units that I am looking for some input/guidance on. I’m sure that it is something simple that I am missing. In the example screenshot, you’ll see that I’m call for the value of a specific parameter of an air terminal, in this case Supply Air Flow. The value that I get when calling for that specific parameter, and the value that is listed when I just query the parameters of the element, list two different values. What’s the deal with that? Shouldn’t Dynamo be operating from the same units that are assigned to my project? Any and all input is appreciated. Thanks everybody!





Hi Garret,

Dynamo uses ft3/s that’s the reason your getting those values (1.670), 1 ft3/min = 0.016667 ft3/s. But you can use “LunchBox Get Parameter” node to get exact values. See below graph. Good Luck!


Outstanding, thank you very much for the input!

Within revit it stores all values as feet (Feet², Feet³, etc etc) this is why when you get some values in dynamo it is reporting the revit database value not the value in the units of your project. The below image will help show you, see “Value” and “As Value String”.

The node that is shown earlier actually get the As Value String part of the parameter and is the reason it works, so always check the units.

Thanks Brendan, that’s great info!

Hi Garret,

Bumped into that problem as well :wink:
@T_Pover suggested this solution and it works great (and might also avoid other conversion problems…)