Selected surfaces color

i want to change the selected surface color
so i did by using code block
but don’t work…

how can i do?

The node GeometryColor.ByGeometry only shows the color within Dynamo, it does not do anything in Revit.

Also, you are getting an error below because you didn’t put in a Color.

If you want to change the color of a face in Revit, you should take a look at applying paint in Revit to a surface