Set material parameter value <By Category>

[acXBWH8]

Hi everyone,

I have a question about setting family parameter values by Dynamo. What I need is to set material parameter of a family to . According to the posts I read, you should simply use Null as a value (value, that is sent to input of “Element.SetParameterByName” node. Problem is, that when the original value is a Revit material from the project library, the Null value can not overwrite it.

Please, does anyone know a solution or workaround for this issue?

Many thanks!

[SeanP]

You need to pass ElementId.InvalidElementId in python or -1 if just using regular nodes.
https://www.revitapidocs.com/2015/08ae8886-6ab3-3ef5-d2e0-0da2ffa7bd2c.htm

[sovitek]

Hi @acXBWH8 …not sure if this could help…

Set a Key Schedule Parameter back to (none)

Hmmmm… try using an invalid element? (Select by ID, -1 as the ID, feed that). Might not work though. This may require a more direct Revit API interaction (IE: Python, or a custom zero touch node) to ensure the right override.