The problem right here is that grass doesn’t reflect light like this. I believe I’m doing something wrong with specular and roughness map. I already unchecked sRGB in the texture. Actually, I don’t really understand what it does and when I should uncheck it.
In the last image, specular is 0. It looks better, but now it doesn’t reflect light at all. Multiplying my roughness map gives me a similar but better effect (since light is reflected). Still not what I want.
I downloaded some textures from there and it seems that all of them suffer from the same problem.
So I guess all of them have a bad roughness map? Should I just multiply them to a high value?
Instead of multiplying you could use Lerp node the same way you did the color, but instead of float value in alpha use this roughness texture. A and B will be your minimum/maximum values for roughness driven by original texture, so you could tinker more to get the appropriate for UE4 result
You should also double check that your Roughness(and any other grayscale texture) is set to Linear. Otherwise, it’s being treated as an even darker image due to gamma correction.
They’re all set to Linear, except Color and Normal maps. I don’t know exactly what each one means. I mean, why all grayscale textures are Linear Color and not Grayscale? Also, when should I check sRGB and when should I not?
I feel like I’m doing this wrong, but it’s indeed looking better. The first one is with the new method and the other is with specular = 0 for comparison. Is that what you meant?