Thank you all for the help. @NilsonLima asked what is the Specular of the grass inside MF_Grass01, and the answer is it’s using the default Specular, because no connected node, I think it’s 0.5.
Anyway, I give up my method because the path doesn’t look realistic, and I don’t know how to make it looks better, maybe I must give up this method.
I think I’m going to go more wild to solve the problem, I mean use a tessellated path and spread some plants on the path. That’s the only solution I think. Does anyone have an idea?
Park From Lucid Dream
Let me talk about my art, I’m going to make a little animation. I use Unreal Engine for Hobby, that’s why I can make a better work. It took 20 days to prepare the trees and plants because the materials weren’t directly ready, the Object Space Normal Maps for the rocks were so complicate for example. And it took only one day to make this scene by using the assets with foliage painting, you saw me posted this thread yesterday without anything on the scene. It’s a hobby, that’s why I could be patient for 20 + 1 days.