попробуй
var rand = load("res://addons/random.gd"
.new()
func _ready():
for i in range(0, 50):
var grass = sprite.instance()
grass.position = Vector3(rand.randf_range(-50, 50), 0, rand.randf_range(-50, 50))
grass.scale = Vector3(rand.randf_range(0.5, 2), rand.randf_range(0.5, 2), 1)
grass.rotation = Vector3(0, rand.randf_range(0, 360), 0)
add_child(grass)