I believe John Pierson tackled this one in his app to convert ceiling grids to model lines so they can be seen in other programs like navisworks.
To my understanding it requires the user to manually recreate the pattern in dynamo or c# by reading the properties of its base pattern (either grid spacing, or the source .pat file). From there given a rotation and origin of the pattern, it’s written as an algorithm. I don’t think the pattern lines are immediately available to dynamo as geometry.
Edit: maybe I’m mistaken… time to look into genius loci. I’d suggest showing the node in your solution so other users in future can use it too.