The node is putting out an error since its a bunch of complex piping geometry.
Im just trying to find the point where these pipe fittings go through the wall, theres a flanche in the middle of the wall, so surely i should be getting a intersection with the wall geometry right?
What’s coming out of the ListClean node?
First guess is your list levels.
I’d try a real List.Clean node not that custom node version. Make sure keep indices is set to false.
Also, are you sure IntersectAll is what you want to use here?
https://dictionary.dynamobim.com/#/Geometry/Geometry/Action/IntersectAll
If one solid in the list of others doesn’t overlap with anything else you’re going to get an empty list…
Welp…
There goes my entire evening 
Ok i switched to geometry.intersect, now it does work, sort of 
It’s not perfect but already so much better than doing these manually without being able to snap to them…:
The blue cilinders are the automatically placed families on intersection points. These DWG files are so huge and contain meshes and stuff that dont work well in Revit. I do wonder if theres a better way to find these wall inserts instead of clashing solid geometry…
When you load it into Revit some of the geometry is lost, and thats why some pipes arent clashing. Like these for example:
For reference, the difference between cad source and Revit import:
Revit
Autocad
For some reason all these 3D solid cylinders are lost on import