AI Development Guide and M27AI v10 Devlog


Following the recent Supreme Computer Cup I was inspired to have a go at developing a basic AI for FAF. As I had zero experience of coding in Lua, I thought at the same time I would write down things as I learnt them to have both a guide for other people interested in getting started in developing an AI, and a dev log for the creation of my AI.

See below for a link to the current AI development guide and devlog:

The current AI has been uploaded as a mod, and the files can also be accessed from the below:

I've copied the current overview from the guide below:

This document is intended to do 3 things at once (meaning it does none of them very well!):
• Act as a guide to people new to FAF AI development, including collating any other useful resources out there on AI development
• Be a sort of dev log of my thought process and development steps for creating my first FAF AI, with extracts of code thrown in
• Form my main ‘todo’ list for further developments of my AI
If you see any errors, or have any comments or suggestions (in particular any AI developers who read this since you’ll probably know better/easier ways of doing things than the methods I’ve chosen) let me know and I can update the guide where relevant.

If you’re here for useful resources and/or details of how to write AI and don’t care about the dev log aspect then just skip to section 2) Setup and background and section 4) Index of useful functions, and/or browse the index for points that may be of interest.

Latest changes (v10) summary:
Anti-turtle logic:

  • Use of T2+T3 MMLs and mobile arti to break firebases
  • Ecoing when we have map control
  • Reduced turtle feeding

Other smaller changes:

  • Large bomber attack for if we end up with lots of spare bombers
  • T3 air factories can be built/upgraded
  • Support factories will be built/upgraded instead of HQs
  • Higher tier power is built sooner
  • Engineers can request guards
  • Various bug fixes (see section 3.30.2 of the guide)

Key areas of focus by version (history):
v1-3: Release
v4 - Intel and threat detection
v5 - Use of ACU
v6 - Hotfix for patch
v7 - Engineers and building upgrades
v8 - Hotfix (fixed crash)
v9 - Air
v10 - Anti-Turtle

M27AI developer; Devlog and more general AI development guide:

  1. Overview 18
    1.1) AI goals 18
    1.2) Background 19
    1.3) Approach 19
  2. Setup and background 20
    2.1) Lua editors 20
    2.1.1) Intellij IDEA 20
    2.2) Other guides which include a section on AI: 21
    2.2.1) General information: 21
    2.2.2) How AI in FAF works 21
    2.2.3) AI markers and how AI uses them: 22
    2.2.4) Hooking (e.g. replacing/appending existing game code) 22
    2.2.5) Creating custom scripts for Sorian AI: 22
    2.2.6) Pathfinding 22
    2.2.7) How platoons work 22
    2.2.8) AI Research (non-FAF related) 22
    2.3) Lua coding 23
    2.3.1) How to code in Lua 23
    2.3.2) Stand alone Lua code testing 23
    2.3.3) Lua optimisation 23
    2.3.4) Common causes of errors for non-Lua coders 23
    2.4) Debugging in FAF 24
    2.4.1) Console 24
    2.4.2) Cheats 24
    2.4.3) Log window and error messages 24
    2.4.4) Debug window and shortcuts 25
    2.4.5) Platoon names for debugging 25
    2.4.6) Fast speed 25
    2.4.7) Other shortcuts and game startup options 25
    2.4.8) Suggested shortcut 26
    2.4.9) Using FAF Develop 26
    2.4.10) Error handling 27
    2.4.11) Optimisation – benchmarks and monitoring 28
    2.4.12) Debugging via replay 30
    2.5) AI development discord 31
    2.6) Core FAF Lua files 31
    2.6.1) Accessing core Lua code 31
    2.6.2) Other built in functions 32
    2.6.3) Unit blueprints 32
    2.7) Testing AI against other AI 32
    2.7.1) Simple offline testing 32
    2.7.2) Mass offline AI testing 33
    2.8) Getting started – using a simple AI template as a starting point 33
    2.9) Downloading and setting up MicroAI 33
    2.10) Giving the AI mod your own name 34
    2.11) General - Hooks, and getting the code to recognise if it’s running your AI 34
    2.12) Github 35
    2.12.1) Linking Github with a local repo via creating your own init file 35
    2.12.2) Pro Git ebook 35
    2.12.3) Git commit messages 35
    2.13) Uploading your AI to FAF 35
    2.13.1) Pre-upload checklist 35
    2.13.2) FAF rules on uploading mods 35
    2.13.3) Uploading to FAF 36
    2.14) Other AI documentation 36
  3. AI changes 36
    3.1) Build order - Changing the initial build order 36
    3.1.1) Adding/removing buildings 36
    3.1.2) Change build order based on map resource positions 37
    3.1.3) Build order conditions 37
    3.2) Build order – ACU builds without moving at start 38
    3.2.1) BaseTemplate 38
    3.3) Build factory and power to benefit from adjacency 39
    3.3.1) Record all mexes on the map, and reference this information 39
    3.3.2) Determine com start position 40
    3.3.3) Identify mexes near to start 40
    3.3.4) Hook onto the core code relating to building a structure at a location 41
    3.3.5) Call build order from custom aiBrain function, to edit how things are built 42
    3.3.6) Adjust build template based on mex location - conditions 42
    3.3.7) Adjust build template based on mex location – build location adjustment 43
    3.3.8) Build initial PGens by existing factory 44
    3.3.9) Adjacency bonus where ACU is away from start location 46
    3.3.10) Referencing unit blueprints for information such as unit size 48
    3.4) Platoons and sending engineers to reclaim 50
    3.4.1) How platoons work 50
    3.4.2) Send the first engineer on reclaim duty 55
    3.4.3) Determine where to send the engineer to reclaim 56
    3.4.4) Identifying reclaim mass value 56
    3.4.5) Find out if a location is accessible by ground: 57
    3.4.6) Mapping reclaim locations and assigning preferred location to an engineer 58
    3.4.7) Don’t send early reclaiming engi if there’s minimal starting reclaim 59
    3.4.8) Issue new reclaim command if engineer becomes idle 59
    3.4.9) Send more engineers to reclaim later (as lower priority) based on the reclaim currently on the map 60
    3.4.10) Send 5 engineers at the start to reclaim and build mexes 61
    3.4.11) Reclaiming trees when no main mass left 61
    3.5) Building and assisting hydro 61
    3.5.1) Check if hydro near start area and have engineer build hydro 61
    3.5.2) Have ACU assist engineer with hydro 62
    3.5.3) Get ACU to continue build order after hydro complete 63
    3.5.4) Subsequent build order changes 64
    3.6) Attack force composition changes and check of AI performance 64
    3.6.1) Build Moar Tanks 64
    3.7) Pre-v1: AI Progress check 65
    3.7.1) Land factory buildings and other build order refinements 65
    3.8) Raiding AI 67
    3.8.1) Raiding behaviour - overview 67
    3.8.2) Queue up move commands for mexes 68
    3.8.3) Identify mexes to target 68
    3.8.4) Locating mexes near to an existing pathing route 71
    3.8.5) Determine when raiders need new targets 71
    3.8.6) Handling complications (stuck units, move orders built on, platoon units dying) 72
    3.8.7) Change factory rally point so units are assigned orders sooner 73
    3.8.8) Making use of platoon names for debugging 75
    3.8.9) Ensure 1 land scout included in each platoon 76
    3.8.10) Use microbots before switching to tanks 77
    3.8.11) Have scouts stay with the platoon 79
    3.8.12) AI scouting, threat detection, and identifying nearby enemy units 79
    3.8.13) Attack engineers en-route: Overview 82
    3.8.14) Tracking when have reached movement points 83
    3.8.15) Determining the platoon minimum range 83
    3.8.16) Identifying nearby enemy units and assessing their threat 84
    3.8.17) Actions based on enemy threat 86
    3.8.18) Avoid attacking enemy mexes for small platoons 87
    3.8.19) Other issues – cheating, walls and min range 88
    3.8.20) Larger raiding platoons 89
    3.9) Large attack wave 90
    3.9.1) Checking when to form a large attack wave 90
    3.9.2) Generalising raider AI 90
    3.9.3) Creating separate platoon AI for the large attack force 91
    3.9.4) Run nearer to base when outnumbered 91
    3.9.5) Recalling nearby raiders to join attack force 92
    3.9.6) Updating threat assessment for ACU health and upgrades 93
    3.9.7) Don’t chase small numbers of faster units 95
    3.9.8) Switch to hunt and kill enemies once reached destination 96
    3.10) Pre-v1: AI Progress check 97
    3.10.1) Summer duel 97
    3.10.2) Theta passage 97
    3.10.3) New issues 97
    3.11) Platoon AI – Generalised approach and further enhancements 98
    3.11.1) Embracing the table 98
    3.11.2) Moving units when shots blocked by cliffs 101
    3.11.3) Anti-stuttering protection 101
    3.11.4) Large attack AI – Rally point for merged units 102
    3.11.5) Raiders assume small numbers of enemies are engis/scouts 102
    3.11.6) T1 Artillery specifically target structures, and spread-attack units 102
    3.11.7) Keep scouts at back of platoon 104
    3.11.8) Platoons with non-Seraphim T1 artillery and no tanks don’t run unless against slower enemy 104
    3.11.9) Factor in nearby platoons when faced with enemies 104
    3.11.10) More T1 arti in platoons once reached certain level of tanks 105
    3.11.11) Don’t treat AA as a direct fire unit when forming a platoon 105
    3.11.12) Build hydro where it’s far away from base 105
    3.12) Expansion bases 106
    3.12.1) Background – expansions and the main base 106
    3.12.2) Having all units treated as available for platoons 106
    3.13) Upgrade ACU with gun and attack 107
    3.13.1) How to upgrade an ACU 107
    3.13.2) Get enough energy to support guncom 108
    3.13.3) Upgrade ACU’s gun once have enough energy 108
    3.13.4) Attack with ACU once upgrade finished 109
    3.13.5) ACU overcharge 110
    3.14) V1-3 release incl AI progress check 110
    3.14.1) Performance – v1-3 of M27AI 110
    3.14.2) Issues and planned improvements from testing 111
    3.14.3) Debug issues and other bug fixes 112
    3.14.4) Attack lauched as soon as ACU gun ready 116
    3.14.5) Default attack-move direct fire units at enemy (attack-move if platoon scattered) 116
    3.14.6) Limit of 1 microbot per early raider platoon, and tank defenders 117
    3.14.7) Skip move location if are closer to the next move location than the first one 117
    3.14.8) Build more engineers if are close to overflowing mass 118
    3.14.9) Add energy storage requirements to ACU initial land factory build order 119
    3.14.10) ACU and Engineers will move near mex to build 119
    3.14.11) Other minor misc changes 121
    3.15) On demand basic pathfinding 122
    3.15.1) Revised approach 122
    3.15.2) Mex raiding path optimisations 123
    3.15.3) Useful maps for testing map based logic 123
    3.15.4) Move to build structure – check pathing 124
    3.15.5) Platoon Merge location – have it check no pathing issues in nearby segments 124
    3.16) AI Overseer - responding to enemy attacks 124
    3.16.1) Overview 124
    3.16.2) Planned initial logic 125
    3.16.3) Run overseer on AI creation 125
    3.16.4) Assigning units to defender platoons 126
    3.16.5) Recording enemy threats 127
    3.16.6) Sending units to deal with enemy threats 129
    3.16.7) Sorting a multi-dimensional table 129
    3.16.8) Disbanded units return to base 131
    3.16.9) Intercepting platoons should leave at least 1 scout when removing spare units 131
    3.16.10) Don’t remove units when in combat 132
    3.16.11) Platoon and other build conditions 132
    3.16.12) Limit number of mobile AA in an intercepting defending platoon 133
    3.16.13) Remove ACU from defender platoon once the threat is dealt with 133
    3.16.14) Don’t have ACU join a platoon if its upgrading 133
    3.16.15) Disabling sorian base manager distress logic 134
    3.17) AI Overseer – Intel and ACU managers 134
    3.17.1) Intel manager - overview 134
    3.17.2) Planned logic – 1-off 134
    3.17.3) Planned logic – recurring 135
    3.17.4) Scout localised platoon AI 136
    3.17.5) ACU manager 137
    3.18) V4 release (incl AI progress check) 138
    3.18.1) Pre-release checklist 139
    3.18.2) AI performance results 140
    3.18.3) Notable issues noted from performance 140
    3.18.4) Resolution of immediate issues/bugs post-release 141
    3.19) ACU –aggression, support and micro enhancements 146
    3.19.1) ACU custom platoon - overview 146
    3.19.2) ACU expansion – choice of location 147
    3.19.3) Platoon completion actions 149
    3.19.4) Expanding more than once 150
    3.19.5) Getting nearby reclaim and/or unclaimed mexes while moving 151
    3.19.6) Assisting hydro construction (reworked) 153
    3.19.7) ACU defender platoon refinements 154
    3.19.8) ACU Scout helper and general scout build order 155
    3.19.9) ACU MAA helper and general behaviour 157
    3.19.10) Air threat assessment and MAA to build (initial) 158
    3.19.11) Large platoon scout and MAA helpers 158
    3.19.12) ACU attacks independently to large attack platoon 158
    3.19.13) ACU Build order tweaks 158
    3.19.14) Aeon ACU gets both gun upgrades 159
    3.19.15) ACU retreat 159
    3.19.16) ACU kiting 159
    3.19.17) Have ACU attack-move if kiting doesn’t return any action 160
    3.19.18) Manual overcharge 161
    3.19.19) Other misc changes/refinements 164
    3.20) V5 release (incl AI progress check) 164
    3.20.1) Pre-release checklist 164
    3.20.2) AI performance results 165
    3.20.3) Resolution of immediate issues/bugs 166
    3.21) Refinements, basic water based actions, v6 hotfix 166
    3.21.1) Misc refinements pre v6 166
    3.21.2) ACU water based actions – reclaim and move to shore 167
    3.21.3) V6 hotfix 168
    3.21.4) Error fixes subsequent to v6 168
    3.22) Custom build orders and platoon formers 171
    3.22.1) Proof of concept 171
    3.22.2) Initial complications – LABs and no valid units 173
    3.22.3) Related changes – scout conditions; tracking construction orders 173
    3.22.4) Linking production with threat detection overseer 173
    3.22.5) Increasing indirect fire units based on enemy PD usage 174
    3.22.6) Assign MAA similarly to how scouts are assigned 174
    3.22.7) Platoon former – manually assigning platoons based on threat distance 174
    3.22.8) Try to save raider scouts 175
    3.22.9) Not got enough units for a platoon – send spare units to intel path 175
    3.22.10) Call the platoon former if disband a platoon containing combat units 175
    3.22.11) Platoon merger – Periodically combining attack platoons where they’re nearby 175
    3.22.12) Delayed platoon formation 176
    3.22.13) Factories away from main base or with nearby enemies don’t build engineers 177
    3.23) Engineer overseer 177
    3.23.1) Overview 177
    3.23.2) Spare engineer action logic 177
    3.23.3) Nearby enemy logic 178
    3.23.4) Unclaimed mex logic 178
    3.23.5) Threat detector – adjust distance calculation and record 178
    3.23.6) Update engineer names to reflect their action 179
    3.23.7) Clear unit actions if factory idle (unexpected bug workaround) 179
    3.23.8) Have ACU assist assigned hydro builder and build land factory 179
    3.23.9) Retain existing engineer assignments in favour of nearest engineer 180
    3.23.10) Power assignment – longer term requirement check 181
    3.23.11) Optimisations and rollbacks 181
    3.23.12) Adjacency refinements 181
    3.23.13) Misc changes 182
    3.23.14) If an engineer changes its action and its being guarded, clear the current action and commands of the guards so they can be reassigned 182
    3.23.15) Consider engineer actions as soon as a factory finishes construction 183
    3.23.16) Constructing building – first check if part-complete similar building 183
    3.23.17) Building more engineers 183
    3.23.18) Engineers take into account ACU expansion path 184
    3.23.19) Initial engineers keep building mexes until they die or half the map is covered 184
    3.23.20) Have engineers queue up nearby unclaimed mexes and multiple T1 power 184
    3.23.21) Build a second power at the same time 185
    3.23.22) Build more energy storage based on power income 185
    3.24) Building Upgrade overseer 185
    3.24.1) Overview 185
    3.24.2) Refinements 186
    3.24.3) Have engineer overseer switch to assisting an upgrade instead of building a land factory 186
    3.24.4) Pause upgrade if low on resources (and track so can resume later) 186
    3.24.5) Mass stall – pause factories over mexes 187
    3.25) Idle platoon 187
    3.25.1) Army pool platoon and new idle platoon 187
    3.25.2) Approach 188
    3.26) Misc changes 188
    3.26.1) ACU is removed from defender platoons when allocating new threats 188
    3.26.2) Allocating overseers to different ticks 188
    3.26.3) Have defender platoons move in formation 189
    3.26.4) State of game log 189
    3.26.5) Intel path – allow scouts to move +/- 1 path 189
    3.26.6) ACU shots blocked 189
    3.26.7) Enemy ACU threat increase 190
    3.27) V7+V8 release (incl AI progress check) 190
    3.27.1) V7 - Minor enhancements to overseers due to testing (pre-release) 190
    3.27.2) Tracking revision 190
    3.27.3) Choosing nearby engineers based on mex location 191
    3.27.4) Pre-release check results 191
    3.27.5) V8 Hotfix – crash 192
    3.27.6) Other bugs – fixed in v9 192
    3.27.7) Other misc changes for v9 196
    3.28) Air scouting 197
    3.28.1) Determining when we last scouted an area 197
    3.28.2) How often we want to scout areas 198
    3.28.3) Deciding on nearest mex targets 199
    3.28.4) Deciding which area to scout first 199
    3.28.5) Adding via points to journey 200
    3.28.6) Take a detour if a scout has died 200
    3.28.7) Produce air factory 200
    3.28.8) Ignore locations too far away 201
    3.28.9) Number of air scouts wanted: 201
    3.28.10) Air factory unit builder 201
    3.28.11) Available scouts – factor in fuel and make use of air staging 201
    3.29) Air overseer – Bombers and Inties 202
    3.29.1) Generalised scout/air unit management 202
    3.29.2) Find targets for bombers 202
    3.29.3) Determine available bombers 202
    3.29.4) Assign targets to bombers 202
    3.29.5) Bomber production 203
    3.29.6) Make mexes nearer enemy base high priority scout target if idle scout and bomber 203
    3.29.7) Target power if no other targets 203
    3.29.8) Interceptor basic logic: 203
    3.29.9) Interceptor tracking: 204
    3.29.10) Inties built if not enough to meet current air threats 204
    3.29.11) Don’t build bombers if last 3 that died were ineffective 204
    3.30) V9 Release 205
    3.30.1) Pre-release checklist 205
    3.30.2) Post-release bug fixes 205
    3.30.3) Misc tweaks 206
    3.30.4) Initial build order done via my code 207
    3.31) Air overseer – minor enhancements 208
    3.31.1) Air scouts clear current target if it’s already been scouted recently 208
    3.31.2) Stop inties chasing enemy air to other side of map 208
    3.31.3) Send idle air units to refuel if they have <70% fuel or <80% health 208
    3.31.4) Surplus bomber attack 208
    3.32) Indirect fire units 209
    3.32.1) Indirect fire overseer/enhancements to threat detection 209
    3.32.2) Prioritise shields and TMD if near current target and wouldn’t cause us to come within range of an enemy PD 212
    3.32.3) Instead of using the average position of a platoon, use the position of the front units 213
    3.32.4) Improved ACU protection logic 213
    3.32.5) Raider/large related attack/run logic 214
    3.32.6) Pathfinding issues 215
    3.32.7) Disband indirect defenders if their current threat group is all dead 215
    3.32.8) Don’t issue override orders from the overseer if a platoon is attacking or running 215
    3.32.9) Syncronised attacks 216
    3.32.10) Include nearby defensive type structures when assessing PD threat 216
    3.32.11) Minor refinements 216
    3.32.12) Escort expanding engineers with 1 tank 217
    3.32.13) Remove escorts if too many 217
    3.32.14) Target upgrading ACU 218
    3.33) Strategic choices – switching to eco 218
    3.33.1) Stop building tanks and upgrade sooner if have map control 218
    3.33.2) Switch to eco if we have no core platoons we want tanks for 218
    3.33.3) Eco strategy – focus on defence with minimal raiders 218
    3.33.4) Upgrade factories to non hq factories once we have an hq 218
    3.33.5) Switch to eco if mex income not increased recently 219
    3.33.6) Don’t upgrade buildings near the frontline 219
    3.33.7) After upgrading a factory, build an engineer and power as a high priority 219
    3.33.8) Have spare combat units patrol around the mex on our side nearest the midpoint if in eco mode 219
    3.33.9) Keep building tanks in eco mode if we have high mass 220
    3.34) V10 Release 220
  4. Future possible changes 220
  5. Index of useful functions 250
    5.1) Map, game setup and general aiBrain information 251
    5.1.1) aiBrain - general 251
    5.1.2) AI Brain – Economy 252
    5.1.3) Map Markers and start positions 253
    5.1.4) Map size 254
    5.1.5) Terrain info 254
    5.2) Getting a list of units by category, location, or other method 254
    5.2.1) All units that meet a particular category 254
    5.2.2) Units at/near a location 255
    5.3) Unit information 256
    5.3.1) Units on radar 256
    5.3.2) Blueprints 257
    5.3.3) Unit upgrades 257
    5.3.4) Whether a blueprint matches category conditions 257
    5.3.5) Location and pathfinding 258
    5.3.6) Unit’s ai Brain owner 258
    5.3.7) Unit’s current commands and whether it’s alive 258
    5.3.8) Unit bones 258
    5.4) Unit and platoon commands 258
    5.4.1) Building 258
    5.4.2) Assisting 259
    5.4.3) Pausing 259
    5.4.4) Reclaim 259
    5.4.5) Factory specific commands 259
    5.4.6) Movement and attack-move 260
    5.4.7) Transport 261
    5.4.8) Combat related 261
    5.4.9) Stopping 261
    5.4.10) Upgrades 261
    5.4.11) Current commands and targets 261
    5.4.12) Unit status 262
    5.4.13) Change a unit’s name 263
    5.5) Platoon additional functions 263
    5.5.1) Units platoon handle 263
    5.5.2) Get AIBrain 263
    5.5.3) Get units in a platoon 264
    5.5.4) Disband 264
    5.5.5) Platoon exists 264
    5.5.6) Platoon position 264
    5.5.7) Get all platoons 264
    5.5.8) Platoon ai plan name 264
    5.5.9) Add units to a platoon 264
    5.5.10) Army pool and removing units from a platoon 265
    5.5.11) Create a platoon 265
    5.5.12) Change or reset an AI plan 265
    5.5.13) Platoon movement formation 265
    5.6) Weapon information 265
    5.6.1) Get a unit’s weapon 265
    5.6.2) Get information on that weapon 266
    5.7) Time and thread related 266
    5.7.1) Game time 266
    5.7.2) System time 266
    5.7.3) Wait/delay the code 267
    5.7.4) Fork thread (run independently) 267
    5.8) Events 267
    5.9) Other 269
    5.9.1) Visual changes – Draw Circles and Lines 269
    5.9.2) On Intel Change 270

M27AI developer; Devlog and more general AI development guide:


Not exactly an AI comment, but you wanna have things right, right? 🙂

"Lua" (pronounced LOO-ah) means "Moon" in Portuguese. As such, it is neither an acronym nor an abbreviation, but a noun. More specifically, "Lua" is a name, the name of the Earth's moon and the name of the language. Like most names, it should be written in lower case with an initial capital, that is, "Lua". Please do not write it as "LUA", which is both ugly and confusing, because then it becomes an acronym with different meanings for different people. So, please, write "Lua" right!


Thanks, I'll reflect the correct case usage of Lua in the next version of the guide (I'll probably update it whenever I release an AI update so the two are in sync)

M27AI developer; Devlog and more general AI development guide:


So I decided I might actually post something more relevant 🙂

Full stops vs colons – continuing the above example, oUnit.GetUnitId() will return an error, but oUnit:GetUnitId() won’t.

It's maybe worth mentioning why that happens. oUnit:GetUnitId() is syntactic sugar for oUnit.GetUnitId(self). So if you wanna you the version with . you have to pass self as first arg.

F9 opens up the debug window (you may want to change the game resolution to windowed to more easily access this).

That's a log window, not debug. You can open the debugger with Ctrl+F9 or /debug and that's way better for debugging then trying to print things into the log. Since it works as any debugger you are used to, pauses the execution on the line you seleceted and lets you see whats inside global and local variables.

The below link also appears to give a list of core/global functions that can be used (I’ve not tested these to see if they all work, or even if they’re for FAF rather than SupCom2):

It is for FA, some of these functions are documented here

I’m not using Github since I’m working on this on my own, and since I doubt I can get the same ease of use I currently have with changing something offline and instantly seeing the results in-game after a Ctrl+F10 restart. However, Github is used by a number of the AI developers so there’s likely some significant benefits to it.

Git is very useful even if you're working alone, as you have history of changes and you can easily switch to previous versions if something breaks. The game can use files from any location, so for my development, it uses files from my local git repo. It's just a matter of setting your own init file

To keep things simple (as I couldn’t get more complex builderconditions{} with multiple variables to work, despite seeing it being used in other AIs people have done)

So build conditions are defined in a table

BuildConditions = {
    {BMBC, 'BaseEngineersEnabled', {self.BaseName}},
    {BMBC, 'BaseBuildingEngineers', {self.BaseName}},
    {BMBC, 'HighestFactoryLevel', {i, self.BaseName}},
    {BMBC, 'FactoryCountAndNeed', {i, j, pType, self.BaseName}},
    {BMBC, 'BaseActive', {self.BaseName}},

so here, you have 5 build conditions, each in it's own table.

local BMBC = '/lua/editor/BaseManagerBuildConditions.lua'

first value ( BMBC) in the table is thr path the file you wanna use
second one ('BaseEngineersEnabled') is name of the function in that file to use
third ({self.BaseName}) is table of arguments to pass into that function
AI brain is always passed as first argument, and then all other that you specify in the table

So you could rewrite your example to this:

-- Inside the builder
BuilderConditions = {
    {MIBC, 'Is1NearbyMex', {11}}

-- Inside MiscBuildConditions.lua
function Is1NearbyMex(aiBrain, distance)
    local iNearbyMex = MapInfo.RecordMexNearStartPosition(Utilities.GetAIBrainArmyNumber(aiBrain), distance, true)
    if iNearbyMex == 1 then
        return true
    return false

This way you can already specify the distance for chehcking the nearby mexes.

Determine com start position

This function should do the trick 🙂

To help with this, I first wanted to understand what the various variables feeding into it were, so made use of the log function for each variable in turn; where it returned an error due to being a table value that I was trying to put into the log

Best would be to use the debugger to see whats what, as you can open the tables.
But if you really wanna dump the table into the log you have to use LOG(repr(table))


Thanks, in particular for the debug window - I expect using that would've drastically cut my debugging time! I'll update for your comments in the latest version.

Unfortunately I can't get the debug window to work for me (I just get an error message) and some other people have had the same problem. Asking in the AI discord Jip thought that you need to do an install from the cd version of the game not steam but that you may know the exact procedure?

Error message below in case it helps:

M27AI developer; Devlog and more general AI development guide:


unpack this
into \THQ\Gas Powered Games\Supreme Commander - Forged Alliance\coderes\Engine


Don't think I've got that folder with the steam install, I've got the following:
C:\Program Files (x86)\Steam\steamapps\common\Supreme Commander Forged Alliance
(this doesn't have a coderecs folder, and adding one in doesnt resolve the issue)

I've also got the FAF location:
same issue as with the steamapps folder

(just in case I also tried the \Documents\My Games\Gas Powered Games\Supreme Commander Forged Alliance folder but no luck).

Is there anywhere else I may have missed for a steam version?

Although I'd hoped I'd got the CDs for both as well, checking I've only got the CD for the original supcom so cant try a fresh install via disc.

M27AI developer; Devlog and more general AI development guide:


It belong to the game instalation folders, and fast few ppl having this issue resolved it by creating those folders



I am not finished reading your guide, but excellent work so far!


v4 changes (in reality v2, but when I uploaded the mod on its first release I had to rush out a couple of hotfixes where I'd forgotten to remove debug logic and accidently introduced a bug that affected all games!)

  • Fixed various bugs (see 3.14.3)
  • Slightly improved pathfinding performance (see 3.15)
  • New AI logic which will detect enemy threats and send units to deal with them (see 3.16)
  • New AI logic which attempts to maintain intel over the map to stop surprise attacks (see 3.17)

I've also updated the guide to reflect speed2's comments (as well as a couple of other minor points/sections, such as a bit on uploading a mod and some tests that I now run before uploading)

M27AI developer; Devlog and more general AI development guide:


I am stunned.

Really good work, maudlin27!


v5 changes - these were mostly about the ACU, making it more aggressive and less suicidal

  • Fixed various bugs and improved some error handling (see 3.18.4)
    ACU improvements (see 3.19):
  • ACU will try to expand to high reclaim or mex locations, while building on mexes it comes across and reclaiming
  • ACU will have scout and MAA support
  • ACU tries to kite enemies it comes across
  • ACU uses manual overcharge to overcharge optimal targets

Also updated the guide slightly to add details of the AI development discord channel in FAF (separate to the main AI development discord), and a couple of common hard crash errors

M27AI developer; Devlog and more general AI development guide:


v6 Hotfix - My AI broke with the recent FAF patch, so this is primarily to fix that. I was in the middle of more extensive changes so my AI is less stable than I'd like but I figured it's better than a broken one! I've also held off on updating the dev log for this release.

Main changes made:

  • ACU performs better underwater (reclaims units, tries to move to nearby land when it cant shoot)
  • Improvements to ACU overcharge behaviour (it should OC when retreating, and also positions better against enemy PD)
  • Switch to new error handling approach (orange messages now appear in the log with more detail; this also happens when any ACU dies)

Issues currently present I'm aware of (which shouldnt have a noticeably detrimental impact on performance, but will be noticeable to anyone looking at the log):

  • 'MergeLocations' error message on certain maps - should just mean larger platoons dont regroup at a midpoint before attacking
  • 'MexRaider' warning about the final waypoint - in most cases just affects which mexes are targetted (in rare cases might cause a delay in the platoon doing anything)
  • 'Stuttering'/delays in performance on certain maps (e.g. open palms)

M27AI developer; Devlog and more general AI development guide:


V7 Update - T2 is now here! My changes were focused on creating my own engineer and platoon formation functionality (which took far far longer than I was expecting due to various difficult bugs - a lot of work for not much benefit), but at the end I threw in some basic upgrade logic so my AI now gets T2.

Various bug fixes. More notable ones are that the AI should work better on adaptive maps that 'hide' some of their mexes, and should be less likely to try and build on unpathable mexes
Custom platoon formation and engineer functionality. A couple of more notable features of this are that engineers now work together to build 1 building (e.g. power) rather than independently try and build 5 at once, and factor in what mexes theyre already planning to build on when choosing where to expand
Building upgrade logic - AI will now upgrade mexes and land factories (meaning for the first time T2 units can hit the battlefield!)
Load spreading of functionality to help counter the CPU performance hit of these changes
I've also updated the guide for a couple of points (e.g. including a section on events)

As before, much more detail on the changes/my thought process as I went about implementing them is in the dev log.

M27AI developer; Devlog and more general AI development guide:


v8 Hotfix - Fixed a game crash that could happen if the AI lost an upgrading building (thanks to relent0r for for flagging there was a crash), along with a couple of other minor bug fixes.

M27AI developer; Devlog and more general AI development guide:


v9 Reintroduced air units:

  • Air scouts are built to periodically scout locations of interest
  • Interceptors are used to help defend against enemy air attacks
  • Bombers should target enemy units of interest.
  • Air factory should be built early if there's enough power (and by a hydro if one is available)
  • Various bug fixes and small tweaks to behaviour - refer to 3.27.6 - 3.27.7 of the guide

M27AI developer; Devlog and more general AI development guide:


I admire the guide / developers log that you are keeping 🙂

A work of art is never finished, merely abandoned


V10 - Implemented anti-turtle logic:

  • Use of T2+T3 MMLs and mobile arti to break firebases
  • Ecoing (not very well, but better than before)
  • Reduced turtle feeding

Misc changes:

  • Large bomber attack for if we end up with lots of spare bombers
  • T3 air factories can be built/upgraded
  • Support factories will be built/upgraded instead of HQs
  • Higher tier power is built sooner
  • Engineers can request guards
  • Various bug fixes (see section 3.30.2 of the guide)
  • Updated the guide with details on how to run in FAF Develop offline

My AI also has a new icon 🙂


For anyone that's interested in the background to the last 5 versions/2 months - back at v5 I was crushed by gunner1069 (I usually get them to play a match every couple of weeks against the latest AI version) with a simple turtle strategy on Theta Passage - they didnt bother getting any mexes and instead just rushed T2 PD with their ACU and my AI had no answer despite having 4x the mass income. My primary focus in all the versions since then has been coming up with the logic that will give my AI a chance in that scenario.

Unfortunately, a relatively simple plan for a human (dont send units single-file into PD, upgrade mexes and then attack with MMLs) required a bunch of different bits of logic:

  • Checking for PD and running away from it (so the enemy isn't fed kills/mass), without running away when we're already in range of it and able to beat it (I had some frustrating to watch games where my AI would charge in at a firebase, overwhelm the shields, be about to destroy everything, before deciding to run and turning a winning position into a loss)
  • Realising there's PD when it kills our land scouts without being picked up by their radar
  • Making use of air scouts to reveal 'hidden' PD to avoid suiciding units and the ACU into the PD
  • Quickly expanding to uncontested mexes (including on enemy side of the map)
  • Focusing on maintaining map control and ecoing if faced with a turtle rather than trying to break them immediately, which in turn requires various logic for identifying if we're against a turtle, upgrading mexes, building T2+ buildings, upgrading factories, making use of support factories, etc. (I've still not got basic things done like capping mexes with mass storage)
  • Using indirect fire units to attack PD/long range enemy units while both protecting them from enemy mobile attacks, and not suiciding our own units trying to protect them

These changes also mean my AI will be worse in other situations - e.g. against a non-turtle it might choose to eco when it would be able to finish the game by pressing the attack, and it's also still poor at the mid-T2+ stage so extending the game via ecoing means it's more likely to snatch defeat from the jaws of victory. Long term though it needed to happen as a 'T1 or die' strategy only has a decent chance on 5v5 maps.

M27AI developer; Devlog and more general AI development guide:


@maudlin27 Nice list of g
Changes of updates for you Ai mod, I'd like to extend you the offer it have this in a more of a cleaner formate over on the new faf wiki, if this is somtbing your interested in please send me a pm here or on the faf discord and I can set you up with a page 😀

"The needs of the many outweigh the needs of the few" - Spock