Here

I painted this figure recently (1/35) and I think I used the pattern you are referring to.




I simply used a 3/0 brush to paint the jagged green and red/brown patches. The rain can be difficult. I dipped the 3/0 brush in dark green paint and then dabbed it on a piece of paper until most of the paint was off. I then lightly stroked it on the figure and the fine green lines were deposited.

Hard to explain but hopefully you get the idea.

Cheers