Floor Following Topo

Hello Guys,
I have been watching You Tube videos of how to create roads/ floors that follow topo, and I have tried the same methods that’s doing exactly what I want. But,t my Revit floor doesn’t follow topo. I don’t get any errors on Dynamo, soo I don’t know what I am doing wrong. I have tried all sort of things and I cant figure it out. Please help! All your replies are so much appreciated.


Thank you