Create Dimension from Line

Hi, I am trying to create Dimension in Revit by creating Line between two elements. Then I only found out the Dimension.ByElements node but:
1 - I don’t clearly get the concept of this, what are reference elements (In this case I have Grids and Columns)?
2 - Is there any node that help us to convert the Line into Dimension?

I appreciate your help. Thanks so much.

see this topic

Hi Simon, thank you for sharing, but I am trying to creat the Dimensions between Two elements, bot dimension of element.