Curtainwall Panel Sequential Numbering using Excel module in Dynamo

First, thanks for all the generous help thus far in the Forum…

I am working on something similar to this post title. I am using a Graph found at this forum for using a Model Line to order objects, found here: Renumbering Piles with spline model line
So far it is working well. Still, I have a couple of questions.

  1. I can get Curtain Panels to be numbered as long as the Model Line is intersecting. I need the Curtain Panels above and below to share the same number (Mark). In other words, the vertical Curtain Grid establishes a new number for all of the vertical Curtain Panels.
    2017-09-18 4-55-04 PM

  2. Since I’m using someone else’s Graph. Could anyone explain how these nodes are working? You will need to open the Graph to see it all but I have highlighted the specific area I need to know more about. I think once I know more about this I will know more about question 1.

    model line ordering of curtain walls.dyn (43.7 KB)
    model line ordering of curtain walls.rvt (1.0 MB)