# Basic Pathnodes

### By trevelyan

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Presumptions:
That you know how to make a map, add lighting and weapons, and don't have a clue as to how to make bots do what you want in a match.

Forward:
A quick explanation as to how the computer opponents (or "bots") work: Every bot in UT and Unreal have pre-programmed actions that are not changed. When it knows a pickup or weapon is nearby, it will usually grab it immediately. When an opponent is within sight, depending on the settings, it will attack in a pre-assigned manner. (Jumping, strafing and firing) When nothing is nearby, the bot will remain still, and actually pace around a little. What pathnodes do is force them along set paths, in straight lines.

Now on to the tutorial already!
OK, first you need to make 2 rooms; roughly 500x1000, any height. Subtract both rooms and intersect a hallway between the 2 rooms, making the hallway considerably narrow. (See the picture below) Go into your Classes window (on the right hand side) and add your playerstart actor and some lighting. Make the playerstart on the end of one room, and set a weapon or pickup (Under Inventory) behind the corner of the other room. (So if you were walking down the hall in the middle, you would have to round the corner to see it)

Now, go into your classes again, and highlight "Navigation Point> Pathnodes". (Yay!) Right click in front of the playerstart actor (the little joystick icon) and click "add pathnode". A little apple should appear (why an apple I'll never know; must be a temptation thing.)

In this case, you would want to add the pathnodes directly through the hall, meeting into the other end. The picture above is in the other end of the map, where the weapon is. Now if we ran this map with a bot right now, it wouldn't function quite right, for 2 reasons. First, we didn't define the pathways; second, the pathnodes aren't set up quite right in this picture, even with this level of simplicity.

First thing's first however. Hit F8 to bring up your rebuilder. You are probably used to just hitting "Rebuild Geometry", as it does most of the work for you. Instead, click the far right tab (Lighting) and click on "Paths Define", located near the bottom. You won't notice anything until you set up your 3D window to show pathways. Simply click on "View" in the 3D window and click on "Show Paths". You should see something like the picture below:

(Notice the blue and red lines? Those are your paths.)

Now everything is set but one thing. It's better to learn the right way first-hand, so observe closely. The pathnode in the hallway is not in visible range of the rocket launcher. The bot in this map will run to the pathnode in the center of the next room, and then run backwards to the rocket launcher.

No real biggie at first, but a quality map must have bots that behave like humans. Humans don't run back and forth like this one will, so a little more work is needed here. (Most likely you did it right the first time around, but this example will help you anyway)

Now, all that is needed here is the pathnode near the center of the above picture to be moved ahead slightly. Re-define the paths using the Rebuilder. This will create another path, having the bot run straight for the rocket launcher, and then proceeding to the center…

(Hooray! Now it's properly set up! (In actuality, another pathnode closer to the weapon would be a good idea, especially if you are to place ammo there.))

It's an annoying but good practice to "run through" the pathnodes in the 3D window, making sure each one is within sight of another, and is easy to get to. Always make sure that pathnodes form a pattern through a map, and never use weapons as paths themselves; if the weapon is gone for some reason, the path is cut, and another path should be available to it. Also note pathnodes do not work for elevators, but do work for teleporters. Elevators require a Liftexit and Liftcenter, which will be covered later on. It is most important to not overdo pathnodes; you usually don't need multiple paths is say, a hallway or small room. As mentioned earlier, when confronted the bots will move off of these paths and attack, usually furiously. The purpose of them is to guide them through when they are "mellowed out", for the most part. In other words, KEEP IT SIMPLE!
Any questions or comments E-Mail me at connors@nnex.net. I would be glad to help out. Until then, happy frags!