Hello There.
I am currently learnig little things about blender and ue4.
so i started to make very simple things and i wanted to check out my thing!
i took my mesh and put it on ue4.
when i assign a grass Material to it ( just to test it )
i can only see the colour green but RLY only like the base colour and nothing more . i will send in pictures of my “bridge” with the grass material. and another “bridge” (not by me ofc) with the same material. i hope you can help me.!
( i created this thing with blender maybe i must do something there?)
Thx 
you need to unwrap your texture uv’s.
google something like “Blender unwrap uv’s” or the like
thank you very much for the answer sir !