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AI Marching script

This tutorial is to show you how to make any ai monster follow a path. This does require some scripting. Also note, you need to make two .aas files as they contain the information for the bots to navigate etc.

If your making a single player map, chances are you need to have some ai marching or following a path at some stage. Its not that hard to do but hard to get into and understand.

1. First thing we need to do is create our bit of world to test them out. Ive make a simple L shaped platform and a wall in front of the player so the ai cant see him when he spawns so you can check the ai out otherwise he would turn nasty and attack you.

The best way to follow this tutorial is to download the .map file here It looks like in Fig 1.0 and Fig 1.0a

(Fig 1.0)

(Fig 1.0a) Top Down View

As you can see in my haste ive made it on too smaller grid, I usually use grid size 5 but for some reason for this one didnt, since your doing this tutorial you should already know about grid sizes anyway, but if not dont do what I did above, stick to large grid sizes when possible. Anyway our solider is going to walk along that raised platform you see in fig 1.0, he is also going to stop at the ends and turn to face as if he is marching.

3. Once you have your map file, we need to first create where our ai should be going. For this we need to use "ai_markers".

First off right click and chose "ai" then "ai_marker" from the list. What you need to do is place three on the platform, just pop them in like in Fig 1.1

(Fig 1.1)

4. Now what we need to do is give them all names. On Fig 1.2 select that ai_marker circled in red first and press "N" to bring up its properties and give it a key of "targetname" and a value of "point1"

(Fig 1.2)

Our first ai_marker now has a name, we also need to give it an angle to be on the safe side so he knows which way to go when he gets there, although im not 100% sure its necessary it didnt seem to work right without it.

For "point1" ive given it an angle of "360" (Fig 1.3) by pressing the 360 button. I chose this because on my map in relation to the top view, 360 is the direction to walk after he gets to that marker. Although for the other point in the middle he come be going any direction, I dont think it matters about the angles its just when I tried without it didnt work that time.

(Fig 1.3)

5. You dont need to worry about any of the other settings apart from angle and name.

We now need to give the other two ai_markers names and angles. Ive tried to explain it best I can in this high quality picture, note that we havent yet put in the actual ai:

(Fig 1.4)

Hopefully you can understand the jist of it. The red blob will be where we place our actual ai, which will be a soldier (ai_soldier). He will then move to point1 first, so point1 has an angle that directs him back to point2, then point2 leads to point3, then point3 leads back to point 2, so its his patrolling path that we have effectively marked out using the ai_markers

6. So give the ai_markers the correct names, point1, point2 and point3 like in Fig 1.4, point1 has a angle of 360, point2 has an angle of 90 and point3 has an angle of 270.

If you have made your own map to do this and not used mine then it depends what direction you made the map in to what the angles will be. Direct them like in Fig 1.4

7. So now we should have the ai_markers all ready to go. What we now need to do is to put input our actual ai.

Im going to put in a solider. What you need to do is right click and chose "ai" then "ai_soldier" ive placed him like in Fig 1.5, he is the long orange rectangle

(Fig 1.5)

8. Now we need to change some of the soldiers properties, select the solider and press "N" to bring up the entity window. The first thing we need to give him is a name. To do this you give ai names of "ainame" in the value then name them in he key. Ive entered "ainame" then in the key put "nazi1" this is essential, the script will refer to this name to get everything working.

Ive also given him an angle so he is pointing to "point1" at the start, I pressed the "180" button because thats what way in relation to the top view he needs to face.

You can chose your model for the ai_soldier too, ive entered "head" "escape3" and "skin" "infantryss/default" im not sure if you have to enter these, if you dont it will probably just use a default head and skin.

Thats all we need to enter for the ai_soldier, your screen should look like Fig 1.6

(Fig 1.6)

9. Now we have three ai_markers all with names and angles, and a ai_soldier with a name and an angle, what model and skin to use etc.

Thats all you need in the map. Save your map as "aitest"

10. Put your map to one side now, we now need to make our script, which is in fact classed as a ai file not a text script so to speak. First thing you need to do is get a ai file from a pak or someplace, any file that says its an ai file.

I chose "escape1" for mine as it came with the editor. Now copy it, then rename the file the same as your map "aitest", open up the file (right click, open with, notepad) and delete the contents and save.

Now we have our own blank ai file called "aitest"

11. Now ive tried to make this as simple as possible, I myself used the example marching script to understand it so its virtually the same as that. My entire ai file looks like this:

aim_accuracy 0.75
attack_crouch 0.1
idle_crouch 0.1

trigger nazi1 marchloop // This will begin the Marching loop.

trigger marchloop
walktomarker point1
walktomarker point2
facetargetangles point3
wait 4000
walktomarker point3
wait 4000
trigger nazi1 marchloop // Restarts the marching loop.



So there we have our ai file. Its quite simple, on the player spawning our soldier (nazi1) is triggered into following the the script

You may as well copy the script above into your ai file and save it. Some people have reported when they cant get the script to work adding another "}" to the end fixes it, although this script works fine for me and other people so im not sure why some people get that problem.

Example files are here includes ai file, map and bsp file.

12. You should now have your map named aitest, containing 3 ai_markers and an ai_soldier as well as your ai file called aitest. What we now need to do is compile aitest, you should already know how to do this, if not see here Now Just do a normal full compile.

Once that is compiled for any other type of thing you would be finished, but our bot needs to have some information about the map from the bsp. He will not work without it. So go onto the next step and learn how to make your .aas files.

If you get an error pop up in the yellow box saying "expected {" found end, or something similar then this is a script problem and you might of gone wrong someplace. First check the AI script and see if the brackets are indeed in the right place and also check in the map to see if you named the ai_solider correctly. If it still doesnt work ask on the forums. Dont forget you can download the files from this tutorial here

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Tutorial by eyeronik

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