Hi,
This script used to work well to draw detail lines from a topography in 2016. It now gives me this error in 2017.2. Not sure if the node has become obsolete in 2017.2? Any help would be greatly appreciated.
Looks like one of the lines is reporting a null value. Can you wire in a few watch nodes to isolate it? May also be able to use a list.clean node with a true input and simply ignore it.
Thanks Jacob, does this help? seem to be getting null value with the plane
This is what it looks like after running in 2016, past my skill level knowing whats going on 
topography intersection with plane node is possibly no longer working with new version of revit
Yes. That’s the node causing the issue. Is this the same model?
seems to be working now. Think the topo was copied into the incorrect phase from my linked site file for the script to run correctly. Thanks for your help Jacob, sorry about the silly mistake 
No worries. Happens to us all. 
I lie Jacob! haha. Upon further inspection. It is working with sections but not with elevations! thats whats going on
Ah! Ok. What package is that in? I can try and sneak some time to peak at it tomorrow at the end of the day.
Soooooo. It works for some of my elevations and wont pick up the plane for others. can see the elevations are cutting the topo so im not sure what the difference is. Must be something small im missing. Thank you greatly for you time but Ill just try figure out what it is at some point. This is getting embarrassing lol. The Node info is below for your info anyway 
