Overview of AI files creation

You may modify this file to create new computer player strategies. To do so, follow the instructions below and save the file as a text file with an .ai extension. 

The map and resources can make or break the plan for a CP. Without sufficient resources early on, the .AI file won’t continue building. Instead of a bustling aggressive CP, you get a ghost town, especially if you’re killing off any villagers that come snooping around you. Look at the surrounding terrain where the CP is initially placed. The AI doesn’t do well in a highly congested area. Without decent access to resources throughout the game, the CP will stop processing the .AI file and gives up on it. Also keep an eye on the lions. Lions can stop a CP in its tracks. Make sure lions are placed where they will most likely be encountered by the CP in the middle to later stages of the game.

The .AI file needs to have a good progression not only in units built, but also the structures that produce those units. The CP will skip building things if it doesn’t have the resources or a free building for it. When it can, it will go back and try to build what it skipped earlier. This can cause an .AI file to get out of synch with how you intended to build. If you don’t have a good relationship of resources available to the sequence of builds in the .AI file, it won’t matter what you do in the .PER file (although you can help this out a little in the .PER file). The builds get out of sequence, things bog down, the CP can give up trying. In short, the CP will be a loser.

.ai files contain the units, buildings and research that will be performed by the computer player in the general order listed. The computer will will try to progress through the list and maintain what has been built. For example, when a unit or building in the list is destroyed, it will generally be replaced before a new unit or building further down on the list will be created.

The sample list contains one of every item to be trained, built, or researched in Age of Empires. Storage Pits, Houses, and Granaries (although included in the list) can be handled completely by the computer player (if the appropriate strategic number is set for the computer player). In other words, these need not be placed in the list at all; the computer player will build them when they are needed. (Sample List is located in the Docs Directory of your Age of Empires CD).

The sequence of items in this list is important. For example, the Market must be built before a Farm, etc. As long as the game rules are respected by maintaining the prerequisite order, items in the list can be resequenced. The technology tree foldout is a good reference source for the prerequisites.

Items on the list that cannot be built or researched (for any reason) are eventually skipped (the skipping can be controlled by setting strategic numbers in the computer player’s .per file).

If there are already units on the board that are also in the Strategy list, these units will be counted as already created and will not be rebuilt.

Hints & Tips
Here are some tips for creating your own .ai files. The sample file does not necessarily adhere to the principles that follow. Instead, this list is placed in an order that makes the items easy to find so that you may create your own list.

1. Keep the quantity field down to 1 or 2. Higher quantities will cause the computer player to pause on that item until the quantity is fulfilled.
2. Do not research or build an item from a building directly after constructing that building. Example: Don’t place Bowman after Archery Range. Doing so may cause the computer to pause on the Bowman until the Archery Range construction is complete. Instead, put another item between the Archery Range and the Bowman.
3. Do not place two or more items in a row that come from the same building. Example: Priest, followed by Polytheism, Mysticism and Astrology. Instead, stagger items from multiple buildings to ensure that production at one building does not slow progress through the rest of the list. Good example:

   Priest
   Man
   Polytheism
   Man
   Mysticism
   Market1
   Astrology.

4. Limit retrains (see below) of early-age infantry and archers.

   This ensures that when they are killed they will not be retrained. This frees slots (under the population cap) for them to be replaced by higher-level soldiers. The same concept applies to villagers and fishing boats.

5. Limit the number of units trained to approximately 50. When the computer reaches its population cap of 50, its advance through the remainder of the list will slow down. If your list calls for 30 villagers and 30 military units, do the following:

   -Put 10 villagers, or early-age soldiers on limited retrain. 
   This will open slots for 10 superior replacements later.

   -Put the last 2-10 units you want to have trained in the very last line of the file.
   This way, if you exceed the population cap, you will do so on the last item and not interrupt the progress of the list.

6. Start by modifying an .ai file that is already close in content to the file you want to create. If that list is missing certain items, copy them from the list below and paste them into your .ai file.
7. In the Stone Age, the computer must be able to quickly locate forage bushes, trees, and/or water. Failure to do so will cause the computer not to place a Granary, Storage Pit, and/or a Dock. This may prevent your .ai file from reaching the Tool Age, since these buildings are necessary prerequisites for reaching the Tool Age.
8. Test! After you have completed your .ai file, put it into a scenario, give the computer unlimited resources, and observe the build process on x2 speed. Insure that all items are correctly built. Delete items that have limited retrains and ensure that they are replaced with other units. This technique will greatly accelerate your .ai design and development process.

Legend for the prefix to the ID number

Each object in the game has a unique ID number. In the strategy file, that ID number is preceded by a qualifying prefix. The prefixes are listed below:

B – Building – Will be rebuilt if destroyed.

A – Building – Will be rebuilt up to to the number of times specified in the “Limited Retrains” column.

R – Research – Item will be researched if possible. If not possible, it will be skipped according to the strategic numbers.

C – Research – Item will be researched if possible. If not possible, the computer player will progress no further until this critical research is done. For example, if the computer player does not have enough food to advance to the Tool Age, it will wait to collect enough food and will not skip the Tool Age).

U – Unit – Will always be replaced if killed.

T – Unit – Will be trained up to the number of times specified in the “Limited Retrains” column. Example: 1 indicates that this unit will be created once. Once killed, this unit will not be created again.

Breakdown of .AI – Building

Breakdown of .AI – Research

Breakdown of .AI – Units

Thanks to Dave “Bigdog” Pottinger for helping with this.

Breakdown of .AI – Starting your tribe (The opening)

Thanks to Michael “Archangel” McCart for helping with this.

The sequence of items in this list is important. For example, the Market must be built before a Farm, etc. As long as the game rules are respected by maintaining the prerequisite order, items in the list can be resequenced. The technology tree foldout is a good reference source for the prerequisites.

Items on the list that cannot be built or researched (for any reason) are eventually skipped (the skipping can be controlled by setting strategic numbers in the computer player’s .per file).

If there are already units on the board that are also in the Strategy list, these units will be counted as already created and will not be rebuilt.

We are breaking down each line of the Sample Strategy File (.ai) file located in the Docs folder of your Age of Empires CD. So print it out, if you want to follow along.