Hum cool !
I’m not sure to get exactly what you’ve done, can you post a screen capture ?
In the meantime, maybe you can understand better how I make it by looking at this, especially the second picture :
Once you can instance a grid on faces its then possible to extract parallel lines from the grid, and that’s how I got the basis for the planks. It’s the same operation that we did before to separate the roof : using dot products, but this time on edges.
But maybe you can try your own solution to get to a similar result , that’s the cool thing with procedural modeling.
You can get the orientation of an edge like this :
And plug that into a dot product instead of the normal input we did before.