Swaying Trees/Grass

From GameStudio Wiki

This is a very simple action for swaying trees/grass:

//skill1: speed 5
//skill2: power 5
action ent_sway
{
     my.skill21 = random(360);

     while(1)
     {
          my.skill21 = (my.skill21+my.skill1*time_step)%360;
          my.pan = sin(my.skill21)*my.skill2;
          my.tilt=sin(my.skill21)*my.skill2;

          wait(1);
     }
}

Assign the action to the entities you want to sway, adjust it`s parameters and you are done.