Anyone know a decent patrol system?

I added a patrol system that makes certain units patrol to a random point in a certain area every 3 seconds, but that usually makes the unit restricted to a small area because he is constantly turning around and running in the other direction. This also starts to lag the game quite a bit as well.

Does anyone have an efficient trigger that will cause a unit to constantly patrol the area?

Order it to move to random point within 2000 of Patrolling unit.
Don't got WE up but it should work

I don't think it would be a cause of lag. What I do is randomly order units to attack move to zones close of them, attack move instead of patrol, and since it is periodic it is actually a good thing, they look like wandering around.

So I should order them to attack move to a random point in rect every.. 10 seconds? The rect is large.

Thats only a problem if you dont want the unit to travel long distances; besides, like Vex said, its periodic. Just say every 10 seconds attack to a random point within 5000 or somthing. The size wont really matter too much.

I choose a random point in some range of the unit that must be on that rect.

this is the function I use: http://www.wc3jass.com/viewtopic.php?t=276

has there been a way to make a rect follow a unit like Starcraft because ive been trying to make a few units that a hero summon follow him around well running around him or just running wild near him that attack crap nearby then i have some triggers for attack commands ect.

Actually I found a VERY nice system in the Blizzard map "Funny Bunny's Easter Egg Hunt". I guess that would work just fine.