So that's why the AI kicks our ass in the forest!

[Dwarden 1125]

as i posted in the ticket ...

the trees in question

ca\plants2\tree\t_quercus2f.p3d

ca\plants2\tree\t_picea3f.p3d

according to my testing and after verify with 3D artist these trees have view block for AI

(Geometry and viewGeometry are correct for both trunk and tree-top)

so if it's only these 2 trees, then problem is something else, but still checking (weird bug if really happening)

still looking into the 'cause'

Edited January 24, 2012 by Dwarden

[gammadust 12]

@Dwarden Could it be that the discrepancy lies in the way nearTargets return a wrong position/accuracy value? Anyway in test missions AI appeared to be reacting accordingly (firing in the right direction as perceived).

Edit: Also according to this, Fire and View blocking share the same geometry. This would mean that player would also get hit if that was lacking altogether...

This picture shows clusters- density markers in the volume of a branch and uses them for convex component calculation - (bottom part of picture). On right side is fire/view geometry, on left part of picture, collision geometry.

Impact on gameplay

In our engine the AI try to spot you through the View Geometry, just a small part of your body is enough to be able to recognize and track you. When this view geometry is not masking foliage well, the chance that you will be spotted is high

Edited January 24, 2012 by gammadust

[Dwarden 1125]

FireGeometry is different to Geometry which is not ViewGeometry and that's different to CollisionGeometry :)

what interest You is the first picture (comparing A1 and A2 viewGeometry affecting AI vision) not the 2nd

but i will check even that parts :)

Edited January 24, 2012 by Dwarden

[maturin 12]

Ah, that good old link.

I wonder what happened between the devblog and release, because it is nearly impossible to get the AI to shoot through bushes, no matter how much information and commands you give them.

Dwarden, I posted a new mission where the enemy is clearly aware of the player (he goes prone) regardless of the custom script, without receiving any information from sound.

And I asked a question about canopy leaves that should probably have gone here instead.

[Dwarden 1125]

well we have some theory but it will need to be checked in following days ...

if You find more trees / bushes with same problem please add them to the ticket

well fireGeometry tells the AI if can shoot or not ... but that's not detection

(it's more complicated as in case of missing sub-geometry it's reused from other ones but that's not case of these models)

Edited January 24, 2012 by Dwarden

[maturin 12]

I don't know what various trees are called. I can only post missions. I assume that every tree has this same problem.

Because only those mature Chernarus oak trees are actually thick enough to reliably hide a person. So who knows if Takistani trees, with their skinny trunks, have viewblock geometry there?

[Dwarden 1125]

i know which trees are that and already verified it ... hence why i posted the names

and if i say the geometries are there and correct, then they are ...

(as i wrote above the problem is something else and we look into it)

[gammadust 12]

Posting a screenshot of offending tree should be enough to identify them.

Edited January 24, 2012 by gammadust

[dmarkwick 261]

Bring back Durg :)

[Dwarden 1125]

Posting a screenshot of offending tree should be enough to identify them.

we have debug modes for that ;):D:cool:

[gammadust 12]

This might be a long shot but I noticed some trees show an ID (in mission editor) and other ones do not, being the same tree model. Others still show a green circle around them. Might this related with automatic placement of trees vs manual placement?

Correction: What I noticed is that nearTargets did not trigger (white and red smoke on player) but AI DID went prone, if I was behind one of these green circled trees (tested close and far distances).

Mission is saved, I'll post it.

Correction 2: Totaly scratch that, when I saved the mission with another name, ofc, init.sqf was not there...

Edited January 24, 2012 by gammadust
lets not misdirect anyone

[jakerod 254]

This might be a long shot but I noticed some trees show an ID (in mission editor) and other ones do not, being the same tree model. Others still show a green circle around them. Might this related with automatic placement of trees vs manual placement?

Correction: What I noticed is that nearTargets did not trigger (white and red smoke on player) but AI DID went prone, if I was behind one of these green circled trees (tested close and far distances).

Mission is saved, I'll post it.

Correction 2: Totaly scratch that, when I saved the mission with another name, ofc, init.sqf was not there...

The green circle vs. a shaded in green area is defined in the config of the island I think. It only really has to do with object density (# of objects per area) I believe. There is an object density defined in the terrain's config that says if there are this number of objects in this area then shade it green but if it is less than this allow them to keep their individual symbols. I believe that is how it works.

[gammadust 12]

That seems plausible, after Dwarden's assurances, I reached out for less obvious causes, and for a moment there, I thought it was nailed. I later tested both with and without IDs, green circled or not, within green area and out, makes no diference.

There is definitely something wierd going on here though. Found another tree nearby original forest.

click images for full albums and descriptions:

The following tree trunk by contrast properly blocks view, detection, fire.

Enemy detection on map (M) is consistent with information given by nearTargets position after detection is made by AI.

AI does not fire (nor attempts to) in any case.

The following is another series that I will comment later on, but that goes to show the other issue maybe unrelated of 1% visbility being for pratical purposes the same as 100%:

You can see that vanilla Arma target (red circle) coincides with the white smoke position as returned by nearTargets script, and the red smoke showing its accuracy (lack of it in this case).

Edited January 25, 2012 by gammadust

[messiahua 0]

Just of curiosity I decided to test latest beta (1.60.88279) and try to reproduce AI seeing and shooting through trees (branches, leaves) and I made simple mission: http://tacticalgaming.kiev.ua/tmp/ai_test.utes.pbo. The result is that AI knows about me from the start and I'm being killed almost instantly. From my point of view there is no way AI can directly see me. Can anyone confirm?

[gammadust 12]

I can't check your mission right now...

Check this ticket and see if it is the same issue.

The basic setup is: both AI and player in a static position, facing each other, both have their view blocked by a wide enough tree. Does AI go prone (ie reacting to the presence of the player)?

Check map, is enemy location marked (despite view being blocked)?

Make AI "playable", check if same thing is happening.

Report which tree/bush allows AI/Player to detect each other, while they have their view totaly blocked.

[messiahua 0]

Check this ticket and see if it is the same issue.

Not sure if it is related to these specific trees.

The basic setup is: both AI and player in a static position, facing each other, both have their view blocked by a wide enough tree.

Yes, but in my mission there are more then one tree and judging by screenshots these are not ones mentioned in the ticket. Here is what it looks like: http://tacticalgaming.kiev.ua/tmp/screen.jpg

Right top - "ai knowsAbout player".

Does AI go prone (ie reacting to the presence of the player)?

Yes.

Check map, is enemy location marked (despite view being blocked)?

Not marked. I don't know about him.

Make AI "playable", check if same thing is happening.

Tried from AI position and I get the marker on the map and "player knowsAbout ai" is the same, but I can't physically see him: http://tacticalgaming.kiev.ua/tmp/screen4.jpg, http://tacticalgaming.kiev.ua/tmp/screen2.jpg, http://tacticalgaming.kiev.ua/tmp/screen3.jpg

Report which tree/bush allows AI/Player to detect each other, while they have their view totaly blocked.

Unfortunately I don't know how to reliably do that. nearObjects return a lot of different objects.

Edited January 25, 2012 by MessiahUA

[gammadust 12]

...

Unfortunately I don't know how to reliably do that. nearObjects return a lot of different objects.

Dwarden mentioned they can debug that info out of the missions. But a screenshot can be useful too for quick reference, I guess. They are on it, hopefully, the cause will be identified.

[messiahua 0]

Very hope so. This issue is very severe. Sometimes almost impossible to play in forest areas against AI. I made some additional screens in previous post.

[gammadust 12]

This really looks like a different issue, but I have updated the album with comments:

This might deserve its own ticket, let's have it here until I have a mission and maybe more cases...

(Many kudos to maturin for making this nearTargets helpful script)

[old_painless 182]

I can't check your mission right now...

Check this ticket and see if it is the same issue.

The basic setup is: both AI and player in a static position, facing each other, both have their view blocked by a wide enough tree. Does AI go prone (ie reacting to the presence of the player)?

Check map, is enemy location marked (despite view being blocked)?

Make AI "playable", check if same thing is happening.

Report which tree/bush allows AI/Player to detect each other, while they have their view totaly blocked.

Hm, I tried this test mission (AItracking.Chernarus.pbo) a couple of times. Some rather disturbing things happened.

On regular difficulty. Immediately upon start of the mission if I go into the map, there is already a red marking of the AI behind the tree in front of me, and I had no visual view of him whatsoever. I was like, the map says he is south of me, a few metres, where the hell is he? Then I moved a bit and was shot, seemingly *through* the tree trunk, is that supposed to be possible, I mean he only has a handgun and I was moving so the line from his hand to me would be through the tree trunk.

Upon another try, I moved a bit to the right and shot him in the leg which was all that became visible. That killed him??? I would have guessed the leg shot should only wound him. But more strange was that he had a bullet hole in the shoulder region, which could explain him dying, but I only shot at his leg. Weird stuff all around

-OP

[gammadust 12]

...Then I moved a bit and was shot, seemingly *through* the tree trunk, is that supposed to be possible...

This only happens, as I perceive it, because fire geometry may not be exacly the same as the tree trunk view geometry. I stress "may" because from certain angles both geometries in silhuette can be coincident. This would be within expectations...

FireGeometry is different to Geometry which is not ViewGeometry and that's different to CollisionGeometry...

Depending on which binds to which, I interpret this as existing geometry which gets displayed on screen for player view purposes, there is geometry which is for "can fire" purposes, and geometry for AI detection purposes. The one used for fire appears not to be the same as used for detection since even if AI detects an enemy does not necessarily mean it will fire.

The culprit seams to be some trouble with the geometry used for detection purposes alone, or if not the geometry itself the way it is used for that matter.

[Dwarden 1125]

for the other cases please take in mind that AI sees bit differently than human so the chance they spot You is way higher as they don't have % of body recognize or anything like that

anyway what's wrong with the tree remains mystery

(except sort of broken fireGeometry (that would explain AI capable of fire) but that don't explain issues with AI capable see through it as viewGeometry is present)

i assume nobody found same or similar problem with trees in newer data (OA>)

[maturin 12]

Dwarden, I have never been able to get the AI to fire through a tree. The trees in my missions definitely have working fire geometry, although I don't know that it is perfectly accurate.

It is hard to test the OA trees because they are not thick enough to hide a person. It almost doesn't matter if they have viewblock at all. I could however make you a mission demonstrating that the OA trees have leaves with inaccurate viewblock. Another time, maybe.

And I didn't make that spotting script, btw. It's been floating around for a while and has taught me tons of stuff about the AI.

[domokun 515]

for the other cases please take in mind that AI sees bit differently than human so the chance they spot You is way higher as they don't have % of body recognize or anything like that

That's an interesting remark. In fact I've often wondered how AI spots targets. In my mind's eye, a solution might be to require AI to see a certain % of a target before confirming it as a threat. This could also be combined with the 4 levels of alertness to provide richer, more believable behaviour:

[unit x] spots [% of target],

if [% of target] > [unit X's chance of observing] = [unit X] spots the target (changes state to Danger?)

if [% of target] = [unit X's chance of observing] = [unit X] unsure of the target (continues looking at target?)

if [% of target] < [unit X's chance of observing] = [unit X] disregards the target (remains in current state)

where [unit X's chance of observing] = [unit X observation skill]*[spotter state]*[distance]*[ambient light level]*[target's speed]

where [% of target] = percentage of model that is not blocked by viewGeometry

Examples:

[spotter state]; stealth, danger, aware, safe

[unit x]; 1.0, 0.8, 0.9, 0.7

[target's speed]; halt, marching, running, sprinting

[unit x]; 0.1, 0.8, 0.9, 1.0

This check could be repeated every [delaySpot] seconds a parameter which describes a unit's level of alertness (low for SF, medium for regulars, high for conscripts, etc.)

IMHO this would significantly improve the gameplay, particularly the stealth aspect.

If this could be combined with a semi-realistic audio triggers (inc. AI triggered by player VoIP) then we'd be close to Spec Ops nirvana

Edited January 26, 2012 by domokun

[maturin 12]

A recent test of mine suggests that the AI primarily recognizes bodies by seeing the head and upper torso. It can't tell legs from tree trunks.