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Analysis Of Military Tactics For Adaptation In Ai


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#1 LeFire

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Posted 21 February 2004 - 01:19 AM

Here's a little adaptation of real-world tactics that battlescape AI programmers for xenocide might find useful.

Weapon Deployment.

Rapid-fire automatic weapons:
These weapons should be deployed on ground level, preferably near the edges of the map. The AI can probably do this by spawning aliens with rapid-fire weapons at the edges of the map to catch player (XCOM) forces in the middle with a lethal crossfire. By placing MG-type weapons at the sides, the aliens can get defilade fire, hitting those in the middle even though guys at the edge of the XCOM formation might be missed.
These "machine-gunner" aliens should be mentally-linked to each other for maximum player challenge... When one fires, the others will automatically know the position of the advancing XCOM line and start spraying (at reduced accuracy due to being beyond visual range) in the general direction. If more devastating alien AI is wanted, nearby hidden aliens will also begin lobbing grenades/blaster bombs pver buildings/terrain into the middle of the XCOM formation.

Antitank-type weapons:
If the aliens deploy a weapon with the specific intention to destroy XCOM tanks (for example, a high damage single-shot weapon), it should be spawned on an alien positioned on high ground/rooftops. Real-world tanks typically have low armour values on top and a lousy ability to aim up. Aliens should exploit this.
After the alien takes a shot from the edge of the building, programmers should make him pull back so as to frustrate the player's (XCOM) attempts to shoot the tank-sniper (until someone gets close enough to toss a grenade up).
If more AI difficulty is wanted, make the tank sniper release a smoke grenade before or after the shot is made. Either that or lob a few grenades down after retreating from the edge of the building to kill XCOM forces trying to close for grenade toss (onto the roof).

Splash-type weapons:
Includes stun launchers and blasters. Position these on high ground so that even if the shell misses, it nails XCOM troops with splash damage. Also program these guys with the retreat-after-shot AI.

Sniper-type weapons:
High ground. AI should be programmed to shoot either the XCOM trooper with the heaviest weapon in sight or the highest ranking one. Upon being detected, AI can be programmed to either retreat the alien back into the building or blow a smoke grenade at its feet.

AI ambush
Ambushes for the AI might be difficult to code in turn-based... Real-world ambushes rely on getting the enemy into a "killzone", then signalling the 'open-fire' command either with command detonated mines or the ambush commander firing himself. All ambushers than open fire simultanously and devastate the ambushed.

An equivalent for the AI would be to make most aliens hold fire (even if they an see XCOM units) until more than a certain number of XCOM are in sight OR XCOM opens fire OR XCOM stays in sight for more than a certain number of turns. Upon detection, aliens with direct visual sight with XCOM will fire at the highest ranked/heaviest weapon XCOM troops. Aliens within range but not in sight would simultanously toss grenades into the XCOM formation over terrain obstacles/buildings.

Aliens taking cover

Aliens might learn how to take advantage of holes in the ground in late game or higher difficulty settings. Easy for them to intercept TV shows of soldiers in trenches/bunkers in war movies. The longer the player takes to react to a crash site, the more likely the aliens would dig in or construct makeshift bunkers out of alloy pieces from their crashed UFO in a perimeter around their craft.
On higher difficulty settings, aliens might even camoflage their bunkers as a stand of trees. Some might even place shrubbery in front of their firing ports and shoot through/destroy the plants when they decide to open fire. Others might make bunkers that have shooting ports facing the UFO doors but camoflaged on the side facing away from the craft.

Besides the traditional alien-camping-around-the-corner, other sneakier aliens (say, Greys) might be programmed to spawn in buildings covering the UFO door... facing backwards. Players advancing to the doorway without securing nearby buildings might get a plasma blast (or a blaster bomb) in the back.
More aliens might be programmed to plant themselves over stairwells in blind spots to shoot any climbing XCOM troopers in the back or lob grenades down stairwells.

Some of the aliens that spawn on second-floor barns can be programmed to shoot holes in the floor... upon sighting XCOM forces below them, they can drop nades downstairs... Or a melee-type alien (say, a Spawn) might decide to drop through the roof.

Aliens can be programmed to camp the UFO doors on higher difficulty settings or later in the game, making it essential for the player to research breaching charges or gain access to UFO using other means and directions.

#2 red knight

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Posted 21 February 2004 - 07:04 AM

Excelent resources, someone mark this thread... and keep them comming. I am interested in how we can recognize those special places to position the alien... cause if we can recognize it in a map, we can flag those special places for the AI to use (that is the most difficult part)...

People please, try to do not spam this thread. Think as it as an in development document. Contact LeFire for additions.

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#3 Breunor

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Posted 21 February 2004 - 12:11 PM

It could even be a model or two we make for each landscape type, and there could be a percent chance on each mission that the ambush model is loaded. I can see making various groups of trees for example to use normally in the battlescape, and the ambush version would only be slightly different. You would have to take the time to look at the "typical spots" to be sure. Later when line of sight and fog of war are integrated in the game, you'd have to step into the ambusher's firing arc to be sure, and then it's too late...

#4 dipstick

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Posted 21 February 2004 - 01:41 PM

I hope this is for genius level at above or something??!! I wouldn't want to face these tactics on beginner!
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#5 LeFire

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Posted 21 February 2004 - 08:32 PM

Well, most of us who select Superhuman want a challenge... Hehe. :devillaugh:

I'm just trying to think of ways to make the AI lethal without making it too cheap.

For the map flagging, I think that the UFO doors should be flagged as a "no-go" area for XCOM forces... meaning that nearby aliens would try their best to stop any XCOM from apporaching there? I'm not sure about flagging, btw, not having any knowledge whatsoever of programming.

More thoughts about bunkers:
Fake/empty bunkers. These can be spawned on the map to fool players into blasting them into bits only to discover that there's no one home in the first place. For additional difficulty, spawn the blind-side doorway (not shooting port) of the bunker facing another active one that is highly concealed (probably with the shoot-thru shrubbery)... An XCOM trooper attempting to check out the fake bunker will be shot in the back.
For Superhuman players, rig up a "fake target" in the bunker or equivalent. Maybe it gives a 'valid target' return when the firing cursor is placed over it (I remember using the firing cursor in XCOM 1 and 2 to see if the thing turns yellow over suspicious dark shapes... a little cheap trick).
OR for extreme player pain, replace the fake target with a tied-up civilian in a chair. It'll hurt when you use your last blaster bomb to annihilate the bunker that the aliens stuck poor tied-to-a-chair Farmer Bill in. And your last soldier gets shot in the back when going into the wreck on foot to check out what died. :boohoo:

Explosive mines are no fun when deployed by aliens... so I'll hold back on any mine suggestions at the moment.

#6 Deimos

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Posted 21 February 2004 - 09:04 PM

I don't think there's anything hardcore about these tactics. I know I'd use the kind of stuff Lefire mentions in any turn based multiplayer game and regularly do in tabletop wargming ;). Dipstick, just becasue they're good tactics doesn't mean they'll be impossible to assault. Though I do applaud your efforts to remind us all that not everyone is a superhuman player and we should consider all types of player, not just the hardcore.

I'd say the tactics should stay within their framework and be used all the time but the difficutly setting dictates the ferocity of the aliens deploying the tactics. Things like how well they can set up fields of fire, the accuracy of their shots, if and when they execute pincer manuvers and so on.

Anyway back to the point. As has been mentioned before each race should follow different tactics so I'd say these kind of tactics would be best suited to the Mutons or whatever we're calling them now :P

Each race should have a unique way of attacking/defending so as a general plan these work well but we do need to concentrate on the specifics for each race. How would a Grey use this framework as opposed to a floater.

How would the tactics differ in say a terror mission or a base defence.

For me I see the greys as sneaky buggers who'd use cover as much as possible. ITO (in the original) I used to hate sectoid terror attacks especially at the start as it meant 3 or 4 cyber discs would mow down my troops.

I'd like to see something similar used again. But instead of them just waiting outside your craft, use the grey's innate sneakiness to lul the player into a false sense of security and have them take pot shots and draw the player out into kill zones where the 'pack hunting' discs go to work on the troops with some well placed plasma shots.

I'd have our floaters camp above the ship and 'snipe' as much as possible. The reapers would just be pure viciousness and go straight for the kill.

The Mutons I think we should use them as elites and rival the etherals in player fear. However instead of mind controlling their use of tactics and firepower should have the player quaking.

I don't think we should resort to decoys and the like as in a game there's nothing worse than losing points or lives when you realise it was a decoy. The beauty ITO was that it was you agains the aliens and they killed civvies and lost the player points or the player blew up buildings and lost points because there were civvies inside. Not because the aliens resorted to trickery. Its a bitter pill to swallow.

#7 dipstick

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Posted 22 February 2004 - 02:37 AM

I know you 'want a challenge' but as Deimos says, not all of us want to jump in at that level.

I think that would be perfect for my style - not actually able to make inside the UFO. Maybe the last alien(s) especially greys, stay inside though - to force you to come inside??

I am not so sure about bunkers though? Seriously, do you think that the aliens would have the time to construct bunkers and the like? AND camoflage them as well as other things? Maybe those should be used at the higher levels of difficulty or something - it would be good to have visual difference between the levels to show the player that there is a difference.
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#8 Xer0

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Posted 23 March 2004 - 11:23 AM

How about a stealth factor? It may be hard to implement, but the fighting tactics could have some aspects besides "all out war". For example, inside a house you may be able to sneak up on enemies then quickly sneak into a nearby room. (Vice versa for players and AI.)

#9 jollyrobert

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Posted 01 May 2004 - 08:32 PM

Some of the stuff Le Fire mentioned is really important, but should be easier to code and Xcom members should be able to do it first.

As far as automatic weapons go, as I've mentioned in another forum automatic weapons should be able to 'indirect fire.' In order to indirect fire a machine gun (or direct fire a conventional machine gun for long periods of time - those things put out a LOT of smoke right in the firer's eyes) you need a spotter. It goes like this: when you're firing the machine gun, there's basically a conical region extending away from the machine gunner where the bullets land. A spotter observes the 'beaten zone', which is where the dirt/grass/foliage is kicked up from the bullet landing, and moves it onto the target. Target dies. This is machine gun "indirect," or blind fire.

This spotter can also direct indirect fire, which (for our purposes) includes rifle grenades and blaster bombs (or whatever they are being called now). It also includes mortar fire or heavier artillery, if made avialable (e.g. - attacking cydonia?) This consists of watching where the round lands and telling the shooter how far off.

We, as players, do this all the damn time in xcom, and it is probably way too easy (since every shooter has 'access', if not line of sight, to what every other shooter can see.). THe aliens can't do this, because they see their own part of the map and don't take info from others. We should make it so that the direct shooter, if firign at somethign he doesn't have control of, should be less accurate unless a 'spotter' is designated. Spotters should be able to do other stuff, too.

Jolly RObert.

#10 awof

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Posted 30 May 2004 - 11:24 AM

This should be done with reference to Jagged Alliance 2. In that game, player couldn't bombared the target with multi snipers as accuracy was greatly reduced over distance and range of the weawpon, and further reduced when the 'sniper' did not have line of sight of the target.

#11 Caid

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Posted 19 July 2004 - 12:28 PM

I'm no AI expert, but I have a suggestion. What about making AI copying our own strategies? Analysing moving algorithm and then using it according to mission's success rating, also counting deployment strength, terrain, positioning and other similarities. May seem weird then, but it would be highly realistic. Also it would be a strong challenge for the player. I've seen such learning system in some chess programs.

XCOM with a neural AI, what would be better :D

#12 Cpl. Facehugger

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Posted 19 July 2004 - 06:19 PM

I'm no AI expert, but I have a suggestion. What about making AI copying our own strategies? Analysing moving algorithm and then using it according to mission's success rating, also counting deployment strength, terrain, positioning and other similarities. May seem weird then, but it would be highly realistic. Also it would be a strong challenge for the player. I've seen such learning system in some chess programs.

XCOM with a neural AI, what would be better  :D

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I remember someone proposed that in the labs. IIRC, we decided it was far too much work to implement a fully adaptive AI for our aliens, so it's getting put off to V1+. Of course, my memory hasn't been the best of late.
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#13 Caid

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Posted 20 July 2004 - 04:39 AM

It was just a thought, generated missions may have problems with simple one-set, unadaptive scripts.

#14 54x

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Posted 20 July 2004 - 02:00 PM

On crashed UFO missions, I would've thought that the soldiers would see you coming... and try to ambush you/otherwise stop you from getting inside the UFO. Then the aliens (usually the technicians, navigators, leaders, etc...) inside try and set up a sneaky defense pattern-but they're scared and demoralised, hearing the firefight outside, so good use of Psi or grenades will make them panic.

In Terror missions, I don't think they should be trying to ambush you until you start actually attacking. Then they should try and come up with some sort of plan once you start killing the first few aliens, or if you are really silly and get yourself spotted a lot before you make kills :)

As for Alien Base missions... they should be set up with multiple ambush points, and as you sweep more and more of the aliens clean, their reluctance to use heavy weapons in their own base should drop...

In short, it'd be nice to have some sort of AI "levels" or "states" so that an ambush isn't ALWAYS set up. It gets a bit old if you know that the same variety of ambush is always waiting for you, and you learn how to counter it :) So in missions where the aliens KNOW you are coming, ambushes should always happen. Otherwise, they should be triggered by human behavior- once you've started killing a few aliens, or when you start getting careless, the alien's viciousness goes up and they start coordinating their efforts :)