how can I spread grass all over my terrain without having to do this manually?
I did it with dupliverts but that looks too regular.
Is there another more random way?
I’ve spread the grass all over my terrain with the hair-particle system and weight-painting. looks good in the viewport but since the particle system is only for render it is not working in the game-engine. How can I apply the particle system to be “real” objects?
In the Modifier stack for the object you use for the particle system, there should be a particle system modifier with a button that will let you convert the duplicated objects into real ones.