When i try to push a value to the height value of a planting category im under the impression that it multiplies the values instead of just replacing.
It would be really helpful if we could see the definition?
Sorry i thought i added it to the previous post 
that s most probably a conversion issue inches / meters. convert the double to si units cause height is a length parameter.
I would just add a codeblock like beneath between the Math.Round and the SetParameter node
conversion from mm to feet. (Which is the native Rative format… Many threads have been spent on this! :))
God im dumb as a brick 
can’t believe i forgot about that… so stupid.
Sorry to waste everyones time but thanks a lot
You dumb as a brick? I wrote “native Rative”. Now that’s brick worthy… No time wasted on my part, glad to help!
Ok, i added the Feet to Meters conversion node assuming that the value coming out of my Math.Round was in feet.
Not much better result, my trees are now… 1m tall lol
I included the definition ad the rvt file if someone have time to have a look. Thanks a lot for your help
Interesting that the node doesn’t work but the math calc does. But thanks a million for your help everyone 
@Daniel for me it’s always trail and error too.
I check the result after calculation and then compare it with the revit parameters. if the result is wrong i adjust manually with one of my favorite code blocks 