Yes I have SimpleGrassWind Node Okay now I Disable "Light Map Resolution" and the result are look OK. Right now UE4 are using light map from my Grass Mesh instead right? So this should not cause a problems about "Light map Memory" later right?
Yes I set two sided foliage But right now seem like I find a solution for this Image Below Instance Settings I Enables "Affect Dynamic Distance Field Lighting" & "Affect Dynamic Indirect Lighting" and Increase "Light Map Resolution" from "4" to "2064" and now after Build Light Shadow on Foliage look much more accurate now…