If u are using sprites ( or models ) a seed map might become handy. Check out for
in Manual ( include level.c ).
To keep Performance also check out the CLIP's and DYNAMIC flags
action place_grass()
{
vec_scale(my.scale_x,0.75+random(0.5));
my.flags |= PASSABLE | TRANSLUCENT;
my.alpha = 70;
my.eflags |= CLIP1;
wait(1);
my.emask &= ~DYNAMIC;
}
Maybe you know those nice functions already.
Greets