AI to generate single lines (strokes) instead of shapes

Im trying to use the AI features in Illustrator to create a wood grain effect but in single lines/strokes. 

It is doing a great job of generating the grains but they are all filled shapes (closed paths). 

There is a reason I need them as single lines but I can seem to get it to create lines and not shapes. 

Wondering if I am doing something wrong or the feature can only generate shapes at the moment?

Thank you.