Dimensions between to elements placed along a curve element

Hi Guys,
I am running two objects along a curve on dynamo and I am trying to annotate on Revit the distance from one to the other. I am trying to do so with the Dimensions.ByElement node but i don’t quite understand the inputs required.

Can somebody explain to me how to work with this node as the you tube tutorial don’t seem to be working for me.

Thank you in advance for your time guys :slight_smile: