#gameplay-ai

1 messages · Page 134 of 1

pine steeple
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yo do when changing color

flint trail
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why is this free? what's the catch?

misty wharf
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I mean... what kind of an answer do you seriously expect?

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You'd have to ask the dude who made it why it's free, I doubt anyone here can tell you

hollow gull
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@torpid juniper No it doesn't work in 4.25.4

cold trout
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anyone tried an Custom EQS Test, that would score QueryItems for how far they are to any other valid QueryItem? does that sound practical?

pine steeple
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i mean if you want to sure

narrow pier
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How long has EQS been experimental for? Do you still not recommended shipping games with it?

patent hornet
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its perfectly fine at runtime

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can be a little quirky in aditor

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and at least since 4.13 or so

verbal shore
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There is no good alternative to EQS and Epic Games constantly makes tutorials that includes EQS so I'd say it's OK to use it. I haven't faced any problem yet. But maybe someone did, who knows. 🤷‍♂️

patent hornet
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we do use it in production, no problems so far

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aside from occasional editor crash

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and so far is 3 years

reef flax
#

Just jumping on here currently to ask about a Navmesh related question as well, was wondering if anyone knows much about Overloading the INavRelevantInterface::GetNavigationData( FNavigationRelevantData& Data ) function atm I am doing it on an actor with a static mesh with just
if( static_mesh_ != nullptr )
{
static_mesh_->bOverrideNavigationExport = true;
static_mesh_->GetNavigationData( Data );
static_mesh_->bOverrideNavigationExport = false;
}
in the function this then causes the object to generate navmesh on top of the object using the NavArea class set on the static mesh, without the need to use a NavModifierComponent and its hassle of setting up manual physics brushes/boxes on all of our assets that need a different nav area.

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This is the exact behaviour I was hoping for I think the only other function we overloaded was the GetNavigation Bounds which we just use the BodySetup for the bounds, but all this also leads up to a crash in our Pathfind in a very obscure manor with basically a recursed set of path id's in our nav mesh.

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the only information I can find out about the INavRelevantInterface was from last year which just mentions that you can overload it but not what valid examples are, was just wondering if anyone knows anything about it?

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Also we have custom simplified geometry with convex shapes on near all of our assets if that changes the equation.

night relic
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So I added a "Does path exists" decorator between the actor and the bot point and it fails. I guess that's why the move to node is aborted, but can't figure the reason.

📎 clusterfuck.gif
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This is how navmesh looks, tried with a 100% flat landscape just in case, same result.

📎 laweuasadf.jpg
reef flax
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Is your position you are querying actually on the nav mesh, if you render them out? You can try projecting points to navmesh before you actually set the blackboard member. What type of object are you actually passing into the blackboard there, is it a actor? The AIMoveTo node usually allows an Actor object or a Vector position, whats the default acceptance radius for your pathfinding by default, does it make sense for your world scale?

reef flax
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ok and never mind with my issue for the nav relevancy, found a fix when diffing some of the nav changes on the git, repo for a fix in 4.25 thats not in 4.24 so ported that in and will do our christmas build from source for once yay, less xmas stress 😄

night relic
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What type of object are you actually passing into the blackboard there
ATargetPoint

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@reef flax

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Radius was default, 5, tried many values, currently is 200, makes no difference

reef flax
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your acceptance radius from what I found usually just needs to be bigger than your agents radius from memory

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like their capsule component one

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right so target point is just a empty actor with a scene component, so really just a position, might be worth just trying to change your blackboard value to being a FVector, then setting the value in the blackboard with a

📎 unknown.png
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will hopefully eliminate one variable of knowing if your endpoint is on the navmesh, if thats out of the way then you may want to start looking at settings within the Pawn itself?

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one thing worth trying would be to change your pawns Default Land Movement Mode

📎 unknown.png
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to nav walking which I think might eliminate if you are having issues with physics, as it will ignore any physics in the level and just use the navmesh only to move your pawn

night relic
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ok thank you, will check the API, I'm doing this with code mostly

reef flax
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cool, yeah we overloaded the character movement component for it to default to navmesh walking by default for all characters in our game, you can overload default components with the whole Initializer object

📎 unknown.png
pine steeple
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@night relic i would not do everything in C++

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certain things belong in BP also

night relic
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I have tried pretty much everything at google about the navmesh.
I guess I'm doing something wrong when I build the character.
Will post the relevant parts of the class.
https://hastebin.com/timarozuwa.php

ruby bluff
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does anybody know how to make teleport points in navmesh? For the AI to both recognize the shortcut as a navmesh path and optionally to teleport to the other end of it? NavLinkProxy's doesn't seem to work, or I'm not using them correctly. I'm trying to make sorta infinite area, where npcs can walk off one edge to appear at another edge, and to use it to calculate shortest path correctly.

pastel sierra
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is there any way to make use of FBlackboardKeySelector outside of BT Nodes?

pastel sierra
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nvm, I found it, the owner has to implement IBlackboardAssetProvider

wild plover
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if i want my BT to stay on a statefor some time, i have to use a while loop with a delay ?

pastel sierra
torpid juniper
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This took me a while to grok. But your BT will stay on a given task until it is either aborted or calls finish execute. If you give it a receive execute event, and it doesn't call either of these, the BT will stay on that task forever.

midnight scroll
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Having an issue where my AI are able to step on top of each other. Problem is that these are Pawns with FloatingPawnMovement rather than characters. So I'm unsure of how to resolve that.

pastel sierra
wild plover
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thx, for the answers

night relic
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So about the issue I posted before the Ai doesn't walk the navmesh, I found the capsule component is falling under the landscape.
For instance the character location z is -830.0 and the capsule one -6034.
Not sure if this can be causing the problem, anyway, any idea why it happens?

night relic
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YAY, got it working

flint trail
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when I test AI in PIE and I eject player's pawn, all AI debugging info disappears from the screen

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(then one call up on pressing ' )

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how can I make it stay on the screen even after I eject from player ?

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@patent hornet any idea by chance ?

flint trail
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also got EQS question

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there instances when EQS generates no results and my AI gets stuck in the loop (EQS generates random location behind obstacles; sometimes obstacles end up being outside of the EQS radius and no location is generated)

misty wharf
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Yeah the debug info disappearing is kinda annoying, I've been wondering the same whether there's some way to keep it when ejected

harsh slate
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Ive got a bit of a situation and its rather important, I have one last assignment to do and basically its A* search algorithms and well I just need to make it so my player can see that a certain actor exists within a box component. If anybody is willing to help please do so cause I need this

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basically just need to find where an object is located so I don't walk in that area

flint trail
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@misty wharf I submitted a bug report for this a moment ago.. We'll see if they fix it.

flint trail
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so, back to my EQS issue - I can see that where EQS has no results, my vector variable EQS generates values for is set to "Invalid". Apparently there is no (that I know of) obvious way to check if vector var is invalid or not (there is no Is Valid? node for vectors, only for actors). I am in a pickle with this 😦

lament hemlock
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Does anyone know how to smooth out the characters rotation when using Detour Crowd AI? I have an ACharacter class which I set the "AI Controller Class" to "Detour Crowd AI Controller". I then used AIController->MoveToActor() to move the character and it seems to work much nicer than the base AIController, except the rotation is all jerky, twitching right and left while trying to avoid the other characters?

vocal linden
misty wharf
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oh that's good to know :) @flint trail you might also be interested in above

midnight scroll
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Are there any ways to affect default pawn navigation, or even a dynamically generated navmesh that don't involve having blocking collisions on?

vocal linden
slow bobcat
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@midnight scroll you can use nav areas but, if there's only one path and it goes through a nav area, they will take it. no matter the cost. The only way to completely block AI to go through is to set it to Null.

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General Path question: is there a way to know if an AI character is traversing a nav link? We have logic where we kill/destroy AI if it goes out of nav. I'm prototyping something that would require them using nav links but, while in between points, they are technically out of nav (FindNav fails), so we kill them.
Suggestions?

vocal linden
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How do you verify if a character ran out of nav mesh bounds?

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Literally doing aabb on nav mesh bound and character location?

midnight scroll
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To be fair, that was a pretty vague question. I don't so much care if my AI overlap a little. But I'm finding that having any form of collision, overlap or blocking on my AI drops framerate by about half. Or more accurately I can have twice the ai on screen at the same framerate. This is even if I disable the component's ability to generate overlap events and whatnot. It's totally useless even when it has collision on, they can still walk through each other. But just simply having it on and there drops my AI count at the same framerate to half. So, I've been trying to come up with ways to keep them at least a little spread out without collision.

rough cave
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I have two behavior trees and I think the wrong one is being used. Where do I choose which BT is my controller using?

vocal linden
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@rough cave you specify that in controller. You can chose explicitly by running Run Behavior Tree node in begin play inside controller blueprint/class

rough cave
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so if I don't it just picks one on it's own?

vocal linden
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To be fair I never checked that, but its possible

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I always run it explicitly

rough cave
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aight I was missing this part. I had my AI set up in some test project and now I'm moving it over to another project

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and I think I got everything but this

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thanks

vocal linden
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You're welcome

slow bobcat
midnight scroll
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@rough cave You don't even really need to override the AI controller if you don't want to. You can use the kismet call in C++, or blueprint for SpawnAIFromClass, which will both spawn and apply a behavior tree to your AI. I don't think I've ever even subclassed the AI Controller yet after I started working with behavior trees.

slow bobcat
vocal linden
slow bobcat
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We have 2 right now. Default one, used by the AI only and one we generate with different parameters (generates way less polys) that we use for player stuff

vocal linden
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So, is there an option you could just check if an ai character is inside nav mesh bounds? Or do you have multiple obstacles it can get stuck on while being inside the bounds?

slow bobcat
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I don't think nav mesh bounds are a thing at runtime (not sure, never checked) but, if they are a thing, I wouldn't rely on them, since you migh have a massive volume and just a tiny island in the center. Being within bound doesn't guarantee you are on nav

vocal linden
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True

midnight scroll
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@slow bobcat I'm just testing things out. My actual issue is sweeping movement. Pawn movements use sweeping moves. this is apparently incredibly expensive seeing as I can replicate the same exact behavior on tick with VInterpToConstant with SetActorLocation and sweep enabled. I get about the same numbers. Leaving sweep enabled but disabling the collision results in the same doubling. Leaving collision on, but disabling sweep has the same effect. Which is why I was wondering if there was a way to affect the nav mesh via something other than collisions. I wanted to test if a runtime generating nav mesh updating via pawn locations was less costly than pawns stopping each other via collisions. Unfortunately the pin in that happens to be that nav mesh is generated from collisions, thus I can't test that without another way to affect the navmesh.

slow bobcat
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Sweeping can be expensive yeah.
Leaving sweep enabled but disabling the collision results in the same doubling
this doesn't add up. If there aren't any collisions, what are you sweeping against? since your pawn will be ignoring everything I mean (maybe I'm not understanding what you mean)
Leaving collision on, but disabling sweep has the same effect
Then sweep is not the problem I would say, but I agree it can get expensive
Which is why I was wondering if there was a way to affect the nav mesh via something other than collisions

I wanted to test if a runtime generating nav mesh updating via pawn locations was less costly than pawns stopping each other via collisions```

I think I'm not in the same page. Which one do you want:
a) affect navigation so pawns stop when colliding with each other
b) affect the nav mesh as in "create a hole in it so nav can't go through it".

Question:
- Are you using dynamic navMesh?
- Are pawns affecting navMesh?

Wonder if you are regenerating the nav every time a pawn moves. Because that can be extremely expensive.
vocal linden
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If you are looking for performance issue and you are not sure what exactly might be causing it I would recommend using Unreal Insights. Just make sure you use stat NamedEvents once you start PIE

midnight scroll
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I know what's causing it. Sweeping movements with collisions enabled.

slow bobcat
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not according to you Leaving collision on, but disabling sweep has the same effect
Unless I'm missing something

midnight scroll
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Thus, when I do movements without sweeping, or turn collisions off so that the sweep hits nothing, it's magically faster. That's the problem. So that's why I'm asking if there's any way to affect the nav mesh that doesn't involve collisions.

slow bobcat
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aaaah ok ok. That's a different thing. We're on the same page now

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Ok, I need you to explain it like I'm 5 years old, because this doesn't make much sense to me
that's why I'm asking if there's any way to affect the nav mesh that doesn't involve collisions.
What is your goal exactly? what are you trying to achieve?

midnight scroll
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Just minor detouring. I was hoping that I could create null or obstacle spots in the navmesh where AI would try to go around if there was something there already. I don't need perfect blocking so much

slow bobcat
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aaaah

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I've been there. Your best bet is using Detour Crowd Manager

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tweaking parameters in the settings you can make them avoid more or less, from more or less distance, control how many agents are involved in the calculations, make them take corners more openly etc.
The only problem I have seen is that, in narrow corridors when it gets crowded, you can get agents pushed out of nav momentarily, but it's not as bad as RVO.

I think that your approach is expensive, not because of collisions, but because nav regeneration. What you are doing is to have moving volumes that affect navigation and that forces their current tile to re-generate. Add some more and you might need to re-calculate the tiling. That's expensive.
On top of that you have the swipe which doesn't help.

Try this, keep your expensive approach and run show navigation in the console. Check if your nav is basically red at all times. If it is: bad sign. Red means re-generating. Super expensive.

Side note: Nintendo Switch doesn't suport Dynamic NavMesh

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well, correction: unreal doesn't have dynamic nav when using it for nintendo switch, but there's for nav modifiers only

rough cave
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is there a way to find closest reachable location to provided vector? I'm trying to make my AI run away from player and so far I've made him run to a location specified by some vector math - basically run in the exact opposite direction from player until you're x units away or move closer if you're too far. But of course the AI gets stuck on walls and whatnot with this solution

slow bobcat
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Use eqs. Do a query with min distance from player, point in nav etc and grab the best point

pastel sierra
vast relic
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Anyone here done an influence map? What did your data structure look like?

flint trail
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back to my EQS question from yesterday.. Is there a way to fail Sequence that contain EQS based on EQS output ?

pine steeple
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not with the built in node

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i made my own custom EQS node which is a bit more advanced

flint trail
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I see

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the issue is that there can be a case where EQS generates nothing (vector var is invalid) and I am not sure if there is a way to check if it's valid to fail the Sequence

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(either EQS it the vector var)

pastel sierra
vast relic
real umbra
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Anyone around can help with a basic AI question? I'm trying to do a very basic go to random node using a behavior tree. My AI is set up correctly and the tree is running, but the AI has no active task... ever. Not sure why or how to fix. Anyone help?

real umbra
real umbra
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Needs to be character, not pawn apparently. Moving now.

midnight scroll
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@real umbra MoveTo in the behavior tree works fine on Pawns as well. The only difference between the two if you changed nothing else, is that Pawns require a FloatingPawnMovement component. Where Characters come with the CMC by default.

real umbra
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ah, that would make sense. I couldn't get a simple move to node working either, probably for the same reason?

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thanks for the heads up

flint trail
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gah, this EQS sh!t...

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so basically I fetch a vector from my EQS

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however debug screen (pic 1) shows there is a bool

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how can I get that bool out, cuz I really need to use it along with the vector (which I am already using)?

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I tried adding second EQS node to my BT, but it doesn't work :/

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(basically copy of the original, except outputting into a bool var, not vector var)

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folks, really need help 🙏

flint trail
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dug a bit more into EQS and still have weird issues going 😦

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add bool parameter in the Filter

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which showed up in the Query config in the BT

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If I don't specify BB key in the Query config, debug view looks correct (looks the same with EQS Test Pawn)

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if I specify BB Key as seen above (a bool I want to use in one of the tasks or in a service), things get out of whack:

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all spheres should be blue and yet they are somehow green.

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What I am after is for open areas like that for trace to fail (which is was doing fine before I specified bool var) and set bool so I could use it in BP code. For areas with walls, it will score items behind the walls and fail items in the direct visibility to the AI (which still works with or without bool set in the Query Config)

flint trail
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Hmm... Never mind. I guess Query Config is for passing stuff to EQS, not getting out

flint trail
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OMG, EQS is broken in 4.25

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Get Query Results as Actors always returns 0 actors 😦

flint trail
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reported it

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anyhow, I solved my issue by making custom BTT where I was able to get EQS success or failure

slow pecan
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This might be a stupid question but, i want my aicharacter to switch different animations when he sees me. Like when he is just hunting he is walking, and when he sees me i want him to play his little run animation.

wise iris
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Is there an extra implementation I need to do for defaultpawn to rotate during a MoveTo operation?

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Right now, my pawn seems to be totally oriented the wrong way during the MoveTo, which I never saw happen with Characters 🤔

torpid juniper
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Character Movement Components have a checkbox called orient rotation to movement which handles that.

wise iris
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Yeah, figured I might have to implement something myself, to mimic that (as I have no CMC)

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Had me scratching my head for a moment, but it does makes sense

primal pond
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My AI is trying to chase the player, so I run an EQS query to find the player and then MoveTo location of that player in my behavior tree. The problem is, the enemy keeps running to the location where the player USED to be. Now the player has moved, but the AI is still running the old location. Once it gets there, it will get a new location of the player but the same thing happens since the player is always moving.

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Do I solve this by creating a service that somehow updates the MoveTo?

verbal shore
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Can we use Floating Movement and Character Movement at the same time for AI?

patent hornet
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all our AI have their MovaTargetActors that they move towards

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we never move them to location

wise iris
pine steeple
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@wise iris nope

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our Move to is a custom node

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we can pass in location or actor

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but ultimately its goal tracking, we move a special move target (or attach it if we are moving to an actor)

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this way we can also do a lot of debugging of where the ai has moved too, can see a proper path of the route it took in the Visual Loggger etc

wise iris
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👍

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That's awesome

pine steeple
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we also have custom Gameplay Debugger pages

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showing all kinds of useful stuff

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current aggro on targets, current chosen loc, where we originally started, cost of that path, what navlinks we have on patch etc

wise iris
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I'd be curious to see

ember storm
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anyone know if its possible to have a possessed actor navigate using pathfinding, without using some kind of AI Controller delegate?

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in multiplayer that is.

pine steeple
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No its not

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I mean you could possibly make a custom player controller in c++

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But we have player controlled pawns using both a player controller and ai controller

ember storm
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yea... easiest solution is just to use a delegate ai controller, but give the real player controller input enabled over it, and network ownership, kinda a pesudo possession

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but that did work

pine steeple
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Our player is possessed by the ai controller

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Our observer camera possesses the player controller

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But we have full client side movement on navmesh so player gets instant movement

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Using path finding

ember storm
pine steeple
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Does take some setup and can't be done in blueprint

ember storm
pallid mica
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What could cause an EQS Test to always return null when calling const AActor* itemActor = GetItemActor(QueryInstance, it.GetIndex()); during iteration?
Generator added 24 items, which I can also see in the QueryInstance variable.
And I use the same EnvQueryItemType_Actor for Generator and Test ):

pallid mica
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Tests work if I use a different generator, so something is wrong with mine...
Wondering how much one can do wrong when getting an array of actors and calling QueryInstance.AddItemData<UEnvQueryItemType_Actor>(array);

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ActorsOfClass generator does the same

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The f is this.

This works:

TArray<ASomeActor*> someActors;
for (TActorIterator<ASomeActor> ItActor = TActorIterator<ASomeActor>(GetWorld(), ASomeActor::StaticClass()); ItActor; ++ItActor)
{
    someActors.Add(*ItActor);
}

QueryInstance.AddItemData<UEnvQueryItemType_Actor>(someActors);

This does not work:

TArray<ASomeActor*> someActors;
someManager->GetSomeActors(someActors);
QueryInstance.AddItemData<UEnvQueryItemType_Actor>(someActors);

GetSomeActors looks like this: void GetSomeActors(TArray<ASomeActor*>& OutActors) const;

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:D What exactly am I missing?

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Also tried TArray<ASomeActor*> GetSomeActors() const; and in all 3 cases, the array has the proper Actors in it. But all but the ActorIterator (which I don't want to use) have the Items being returned as null in the Tests.

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That function is a BlueprintImplemetableEvent, which returns an array member. Also tried calling GetAllActorsOfClass in that BP function to return the same actors as with the TActorIterator, but that had the same null problem in the tests.

solar merlin
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I havent used EQS much in general, and not at all in c++, but what exactly seems to be the issue? GetSomeActors fills up the array correctly, but the AddItemData does not work properly?

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as in, at what point when stepping through the code does it not behave like you want it to? @pallid mica

simple crest
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i don't think it is possible to pass arrays by reference through BP

pallid mica
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The Generator has a test on it that uses the Generated Item Actors.

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That Test iterates over the Items and get the ItemActor

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That returns null

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But only if I get the Array via a function

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The ActorIterator "works"

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Both of them seem to add the items peroperly via AddItemData

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I can't see what happens in between all of this.

solar merlin
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why can't you step into the code to see at what point it decides to return nullptr?

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it does sound weird

pallid mica
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They save Raw Data uint8 pointers

solar merlin
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ouch

simple crest
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(why am I ignored)

solar merlin
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you sure hojo? I know at least you can create function parameters and change them to use refs instead

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there you go :P

pallid mica
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So as soon as it's added via the AddItemData, it's not "visible" anymore

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References in BPs work

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But I wrote that I also tried it by value

simple crest
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arg I can't remember proper keywords to find any discussions in CPP

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😄

solar merlin
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sounds like a very nasty bug yeah. I don't see any obvious reasons why this would fail and I can't test rn either, not on my work machine

simple crest
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i am 99% certain you cannot pass an array by reference to BP

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it always copies it

solar merlin
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but he has confirmed the array does get filled correctly

pallid mica
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So, I did another test now. Previously I had the Function that returns an Array.
Now I added the TArray to the Actor in C++ and filled it in BPs (instead of having the Member Array in BPs).
Same freaking result.

simple crest
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no he hasn't, it's a different array

pallid mica
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In the Generator I can see 24 entries, all properly accessible via the inspector.
All getting added. In the test I can see that the QueryInstance has 24 item entries

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All return null

solar merlin
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no matter if its a different array or not, the adding part seems to work with some content so that shouldnt be the issue

simple crest
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what?

solar merlin
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its only accessing the data after it was added that returns null if I understood correctly

simple crest
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if you fill a different array and then try to read it from your original array...

pallid mica
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So basically I did this now:

TArray<ASomeActor*> someActors = roomManagerComponent->TestActors;
QueryInstance.AddItemData<UEnvQueryItemType_Actor>(someActors);
solar merlin
#

he isnt trying to read from the original array

pallid mica
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someActors has 24 correct pointers

solar merlin
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but from the query instance

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its like "AddToInstance(arrayContents)". Instance now has the contents
Then "GetFromInstance(someIndex)"

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as far as I understood it

pallid mica
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These are Actors in the Scene, they also remain valid, if that's what you are thinking.

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Yeah

solar merlin
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if adding works both ways (actor iterator and via the function) then I dont see a reason how it can fail in one way but not the other ThinkEyes

simple crest
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if GetSomeActors is in blueprint, even if you're using reference symbols, unreal copies it

pallid mica
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Generator (you can also insert the other code snippets from above here):

void UHEQG_SomeActors::GenerateItems(FEnvQueryInstance& QueryInstance) const
{
    // Some code to get the room manager
    [..]
    TArray<ASomeActor*> someActors = roomManagerComponent->TestActors;
    QueryInstance.AddItemData<UEnvQueryItemType_Actor>(someActors);
}

Test:

void UHEQT_SomeTest::RunTest(FEnvQueryInstance& QueryInstance) const
{
    const UObject* queryOwner = QueryInstance.Owner.Get();
    const int32 queryID = QueryInstance.QueryID;

    BoolValue.BindData(queryOwner, queryID);
    const bool boolValue = BoolValue.GetValue();

    for (FEnvQueryInstance::ItemIterator it(this, QueryInstance); it; ++it)
    {
        const AActor* itemActor = GetItemActor(QueryInstance, it.GetIndex());<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< NULL
        const ASomeActor* someActor = Cast<ASomeActor>(itemActor);
        if (IsValid(someActor ))
        {
            const bool biggerZero = (someActor->GetSomeInt() > 0);
            it.SetScore(TestPurpose, FilterType, biggerZero, boolValue);
        }
        else
        {
            it.ForceItemState(EEnvItemStatus::Failed);
        }
    }
}
simple crest
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at least IIRC

solar merlin
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@simple crest surely cedric has confirmed with a breakpoint on AddItemData line that the array isnt empty

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as he also confirmed that the instance gets filled with data

pallid mica
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Yeah the QueryInstance and the someActors array have entries.

solar merlin
#

so it shouldnt be that

pallid mica
#

This here instead of Function or public Variable makes it work:

TArray<ASomeActor*> someActors;
for (TActorIterator<ASomeActor> ItActor = TActorIterator<ASomeActor>(GetWorld(), ASomeActor::StaticClass()); ItActor; ++ItActor)
{
    someActors.Add(*ItActor);
}

QueryInstance.AddItemData<UEnvQueryItemType_Actor>(someActors);

I don't know why though. Must be something stupidly simple that I don't see.

#

Ah

#

Let me try something stupid

solar merlin
#

the actor iterator seems the most straight forward so I can see why that would work

pallid mica
#

Yeah

#

I also double check with the build in Generator from Epic for AllActors that the Tests work just fine

#

So it must be the way I retrieve and ifll in the array

solar merlin
#

hmm maybe try returning by value instead like hojo suggested, I dont see how it would make a difference here but just to make sure

pallid mica
#

Okay, looping over the retrieved array and filling the local array by hand makes no diff (why would it..)

#

I tried by value already

solar merlin
#

yeah okay

pallid mica
#

TArray<ASomeActor*> GetSomeActors() const;

#

That's how the function looked like at the start

solar merlin
#

seems reasonable yup

pallid mica
#

I also have other code here that works and I don't see any difference

solar merlin
#

can you check the instance values after you added the actors, if something looks different from when it works?

pallid mica
#

Will check that next

#

Trying to ref the array first

solar merlin
#

kk

pallid mica
#

Obviously didn't work

solar merlin
#

if you refer to unreal provided tests and generators, is there a noteworthy difference in how they add actors?

pallid mica
#

Not at all

solar merlin
pallid mica
# 
void UEnvQueryGenerator_ActorsOfClass::GenerateItems(FEnvQueryInstance& QueryInstance) const
{
    if (SearchedActorClass == nullptr)
    {
        return;
    }

    UObject* QueryOwner = QueryInstance.Owner.Get();
    if (QueryOwner == nullptr)
    {
        return;
    }
    
    UWorld* World = GEngine->GetWorldFromContextObject(QueryOwner, EGetWorldErrorMode::LogAndReturnNull);
    if (World == nullptr)
    {
        return;
    }

    GenerateOnlyActorsInRadius.BindData(QueryOwner, QueryInstance.QueryID);
    bool bUseRadius = GenerateOnlyActorsInRadius.GetValue();

    TArray<AActor*> MatchingActors;
    if (bUseRadius)
    {
        TArray<FVector> ContextLocations;
        QueryInstance.PrepareContext(SearchCenter, ContextLocations);

        SearchRadius.BindData(QueryOwner, QueryInstance.QueryID);
        const float RadiusValue = SearchRadius.GetValue();
        const float RadiusSq = FMath::Square(RadiusValue);

        for (TActorIterator<AActor> ItActor = TActorIterator<AActor>(World, SearchedActorClass); ItActor; ++ItActor)
        {
            for (int32 ContextIndex = 0; ContextIndex < ContextLocations.Num(); ++ContextIndex)
            {
                if (FVector::DistSquared(ContextLocations[ContextIndex], ItActor->GetActorLocation()) < RadiusSq)
                {
                    MatchingActors.Add(*ItActor);
                    break;
                }
            }
        }
    }
    else
    {    // If radius is not positive, ignore Search Center and Search Radius and just return all actors of class.
        for (TActorIterator<AActor> ItActor = TActorIterator<AActor>(World, SearchedActorClass); ItActor; ++ItActor)
        {
            MatchingActors.Add(*ItActor);
        }
    }

    ProcessItems(QueryInstance, MatchingActors);
    QueryInstance.AddItemData<UEnvQueryItemType_Actor>(MatchingActors);
}
solar merlin
pallid mica
#

That's their ActorsOfClass one

#

ProcessItems does nothing before you wonder

#

I have some other project that does this similar and has no problems

solar merlin
#

ah well yah they are using the actor iterator as well. Hm.

pallid mica
# 
void UEnvQueryGen_Players::GenerateItems(FEnvQueryInstance& QueryInstance) const
{
    TArray<APlayerState*>& players = GetWorld()->GetGameState<AGameState>()->PlayerArray;

    for (APlayerState* player : players)
    {
        if (player && player->GetPawn())
        {
            QueryInstance.AddItemData<UEnvQueryItemType_Actor>(player->GetPawn());
        }
    }
}

They add one by one, but I tried that too.

#

I tried & the array the same way but no success

solar merlin
#

thats super weird lol
But surely if they store the data using byte pointers there still has to be a way they check for the actor in their data, so you get a nullptr instead of garbage

simple crest
#

ok, looks like I was mostly misremembering - it's if you attempt to return a array by reference in BP code and keep working on it, that doesn't work. probably not what you're doing

#

damnit baby stop hitting enter on my keebs

pallid mica
#

Items in the Item Array look the same in working and non-working version

#

Na, not doing that, Hojo

solar merlin
#

can you look into the GetItemActor function there and find a significant difference when it works vs. when it doesnt? some condition it fails at in particular?

pallid mica
#

Yeah one sec

solar merlin
#

@simple crest so you can specify an array input parameter as ref in BP and that works but if you return it as ref it doesnt?

simple crest
pallid mica
#

Coolio, the Iterator now also doesn't work anymore.

solar merlin
#

fellow gyazo brother

pallid mica
#

Uff

solar merlin
#

I was thinking maybe it has to do with the actor iterator index

pallid mica
# 
void UHEQG_NavigationalRooms::GenerateItems(FEnvQueryInstance& QueryInstance) const
{
    TArray<AHRoom*> allNavigationalRooms;
    for (TActorIterator<AHRoom> ItActor = TActorIterator<AHRoom>(GetWorld(), AHRoom::StaticClass()); ItActor; ++ItActor)
    {
        allNavigationalRooms.Add(*ItActor);
        UE_LOG(LogTemp, Log, TEXT("[%s] [%s]"), *FString(__FUNCTION__), *GetNameSafe(*ItActor));<<<<<<<<<<<<<<<<<<<<<<<<<< valid
    }
    QueryInstance.AddItemData<UEnvQueryItemType_Actor>(allNavigationalRooms);
}

void UHEQT_DoesRoomHavePlayers::RunTest(FEnvQueryInstance& QueryInstance) const
{
    const UObject* queryOwner = QueryInstance.Owner.Get();
    const int32 queryID = QueryInstance.QueryID;

    BoolValue.BindData(queryOwner, queryID);
    const bool boolValue = BoolValue.GetValue();

    for (FEnvQueryInstance::ItemIterator it(this, QueryInstance); it; ++it)
    {
        const AActor* itemActor = GetItemActor(QueryInstance, it.GetIndex());<<<<<<<<<<<<<<<<<<<<<< invalid
        const AHRoom* roomActor = Cast<AHRoom>(itemActor);
        if (IsValid(roomActor))
        {
            const bool hasPlayers = (roomActor->GetNumPlayersInRoom() > 0);
            it.SetScore(TestPurpose, FilterType, hasPlayers, boolValue);
        }
        else
        {
            UE_LOG(LogTemp, Error, TEXT("Room Invalid in DoesRoomHavePlayers test."));
            it.ForceItemState(EEnvItemStatus::Failed);
        }
    }
}
#

That's the full code

#

:D I think I will stop for today. I have no idea what is going on anymore. Also deleted saved and intermediate

solar merlin
#

okay, but like I said if adding doesnt seem to be the problem I would look into the retrieval itself, how it's performed

#

Ill be back home tomorrow, so remind me to try it out for myself

#

or inform me when you figure it out, because now Im invested

pallid mica
#

Just for the record, the ActorsOfClass generator with the same tests works just fine

#

Radius isn't used on that Generator, so it uses the ActorIterator too

solar merlin
#

its a weird issue for sure

pallid mica
#

I changed the TActorIterator to use <AActor> (but still only search for the AHRoom) and its tarted working again

#

for (TActorIterator<AActor> ItActor = TActorIterator<AActor>(GetWorld(), AHRoom::StaticClass()); ItActor; ++ItActor)

#

............

#

Actually, I changed the array too

solar merlin
#

is this on 4.26? Perhaps a new bug that was overlooked

pallid mica
#

Should still be 4.25

#

haven't updated yet

#

The array being Actor* doesn't make sense

#

I have other examples that have APawn and what not added

solar merlin
#

cant tell you honestly. It seems like a weird internal bug that isnt related to faulty code on your part

pallid mica
#

Maybe. Thanks for your time though. Hopefully solves itself soon

solar merlin
#

for sure

pallid mica
# 
void UHEQG_NavigationalRooms::GenerateItems(FEnvQueryInstance& QueryInstance) const
{
    AHGameState* gameState = GetWorld()->GetGameState<AHGameState>();
    UHRoomManagerComponent* roomManagerComponent = gameState->GetRoomManagerComponent();

    TArray<AHRoom*> allNavigationalRooms = roomManagerComponent->TestRooms;
    for (AHRoom* room : allNavigationalRooms)
    {
        QueryInstance.AddItemData<UEnvQueryItemType_Actor>(room);
    }
}
#

Now this started working

#

Why not a bit more random...

#

And now even this works:

void UHEQG_NavigationalRooms::GenerateItems(FEnvQueryInstance& QueryInstance) const
{
    AHGameState* gameState = GetWorld()->GetGameState<AHGameState>();
    UHRoomManagerComponent* roomManagerComponent = gameState->GetRoomManagerComponent();

    TArray<AHRoom*> navigationalRooms;
    roomManagerComponent->GetNavigationalRooms(navigationalRooms);
    for (AHRoom* room : navigationalRooms)
    {
        QueryInstance.AddItemData<UEnvQueryItemType_Actor>(room);
    }
}
#

I've been through all those iterations already.

#

Anyway,...

pine steeple
#

ewww for (TActorIterator<AActor> ItActor = TActorIterator<AActor>(GetWorld(), AHRoom::StaticClass()); ItActor; ++ItActor) :( ```for (AHRoom* Actor : TActorRange<AHRoom>(GetWorld()))

pallid mica
#

Copy pasted from working code, just to debug :D

#

Still don't know what the reason was

pine steeple
#

i have issues sometimes with EQS not generating properly

#

no idea why it happens

midnight scroll
#

Are there any defaults for making an AI go to the closest point on a navmesh to an actor? In short, I have actors that null out the nav mesh in their area, dynamic generation. I do this because I don't want AI to use this area for navigating, because my AI have no collision and don't run into these actors. But at times AI need to move to the actor itself, or at least close to it, and if I null out the navmesh where this actor is, and tell the aI to move to it, the AI just ignores the movement.

pine steeple
#

use partial path, and you need some kinda breadcrumb system, like last known nav location

#

of the target

#

there is no get point close to point on navmesh

#

you could use EQS to generate some points

#

and choose closest to target, with the correct dot

midnight scroll
#

Allow partial paths is on by default. So basically my only choice is to create something to find a close point on my own?

patent hornet
#

those actors can define a set of points

#

to which AI can go

charred lava
#

After playing a bit around with the Behaviour Tree and Blackboard, I get an unpleasant feeling that I do something wrong regarding maintainability / structure.
Is it normal to have 20+ or 30+ Blackboard variables? I have an RPG project with multiple abilities and that get's multiplied with the weapon's I want to add in. I thought about having an Class Blackboard variable that when set with an Ability class is ready and I unset it when the Ability is on cooldown and that leads to me having a lot of Blackboard values. Is that the way to go? Or how should I pursue this?

pine steeple
#

we use Gameplay tags to overcome that

#

though you can't store a GameplayTag as a Blackboard key, we worked around that by storing the tag in the ai controller, and pulling it

charred lava
#

Thx Kaos!

lyric flint
#

Doing the game ready tutorials, and hitting a wall at the start of ep03. My stats are not showing etc

#

Been back and forth over it, getting an error re: Blueprint Runtime Error: "Accessed None trying to read property CallFunc_Conv_FloatToText_ReturnValue". Blueprint: StatBar Function: Execute Ubergraph Stat Bar Graph: EventGraph Node: SetText (Text)
Blueprint Runtime Error: "Accessed None trying to read property OwningPawn". Blueprint: StatBar Function: Execute Ubergraph Stat Bar Graph: EventGraph Node: Set Percent

pine steeple
#

no idea what you tutorial, but your error is right there

#

OwningPawn has not been set

#

follow the tutorial again and make sure you have not skipped anything.

lyric flint
#

@pine steeple Have it as AIS Character. Went back through the tutorial a few times

📎 unknown.png
pine steeple
#

where do you set Owning Pawn?

lyric flint
#

Not sure that I have tbh

#

Originally it was a cast to AIS_Character set to owning pawn

#

Then they removed it, did some random fuckery, and theirs works and I've missed something

#

After going back several times I'm kind of at a loss as to what I missed or what has changed between 4.11 and 4.26 that might have thrown it

lyric flint
#

That removes the errors, but still does not provide a functional report

lyric flint
#

Got the feeling I'm asking an really stupid question . . . Lol

#

And didnt see anywhere better to ask, its barely tangential to AI

keen temple
#

How to optimize a lot of AI actors? All I need is a thousand actors following the player

pine steeple
#

Don't use the ACharacter, don't use the CharacterMovementComponent

keen temple
#

When I have about 200 - the performance goes off

pine steeple
#

use a multithreaded movement system

keen temple
#

I use the CharacterMovementComponent, yes

pine steeple
#

read what i said

#

DON'T use them

keen temple
#

What is a multithreaded movement system

pine steeple
#

you have to make it

keen temple
#

I read

#

wait till I write the message

pine steeple
#

where all calculations are done off the game thread, and you space out updates on the main thread

#

so as not to saturate a single frame

keen temple
#

Is there an example?

#

No idea at all what is it

pine steeple
#

no idea, maybe google

keen temple
#

You never done it?

pine steeple
#

not many people here have 1K ai chasing a player

#

i have 150 AI max

#

and keep them spawning to make it seem like there is lots coming

#

smoke and mirrors.

regal stone
#

Can someone help me setup a Cancel Movement for my Move to Task? (BT)

midnight scroll
#

@regal stone I just use the same function that sets the movement location initially, but input the aI's current location.

flint trail
lyric flint
#

So I have a need for 3D pathfinding which will involved fairly simple pathing to and from a 'hub' actor. I am thinking to use the fact that all my obstacles are rooted in the ground and use 2D pathfinding, maybe using an invisible character who walks on the ground underneath my flying character to direct movement. I'm just wondering how feasible this is and what tools I have at my disposal for this approach.

regal stone
flint trail
#

not sure what I am looking at - both tasks make character move to location?

regal stone
flint trail
#

are they standard Tasks or the left one is a custom Task ?

regal stone
#

GotoLocation is where the character has to be heading and Moveto Makes the Character actually move

#

Left is custom

flint trail
#

why though ?!

regal stone
#

Do i not need it?

flint trail
#

anyhow

#

MoveTo works until character reaches the destination

#

so you can't just add a Task to stop it

regal stone
#

Oh so do I add something instead or remove it completely

flint trail
#

Either run simple parallel or make a custom Move To task where you can check for a condition for stopping and then stop movement if needed

midnight scroll
#

That's why when I stop my AI, I set their move to location in their blackboard to their current location, they stop immediately

regal stone
#

And combine it with the Move to?

midnight scroll
#

You have a vector named Nav in the blackboard, right?

regal stone
#

Yeah

midnight scroll
#

Just change Nav to the actor's current location.

#

The blackboard value will change, and the node will realize it's at it's target and stop executing.

lyric flint
#

So my level is absolutely enormous in Unreal Units. This has not been a problem so far (all the actors in the level are equally large in unreal units, it's just a dimension thing). However when I get to using the NavMesh it is incredibly slow to generate and play the level as well as I guess costly on memory. Basically the navmesh squares are far too small. Is it possible to tell the navmesh to use larger (in unreal units) squares to compensate for the dimensions of my level?

regal stone
#

I need to explain everything better what I'm trying to create is when the AI interacts with something it stops movement

#

And when that something Dies it continues to the Set location in the NAV

midnight scroll
#

I was planning on using two vectors for my movement in the end. One was going to be a desired location, where the player wants the unit to move to. The second being the actual move-to vector. Certain logic would change the move-to vector, but after all logic completed and the ai needed to start moving towards where the player wanted them to, it'd change the move-to vector to match the desired location one.

lyric flint
#

hello friends

#

I have a hard time understanding how to get navigation to work in my project, even AI move to is failing

#

I want to move the wasp a little bit forward roughly to where the arrows are

lyric flint
#

Doing some debugging looks like my movement mode is considered to be 'falling'? Even though I set gravity to 0

regal stone
lyric flint
#

turns out my destination was too far off the ground :/

midnight scroll
#

Does NavMeshWalking not show up in the details when clicking on an AI? I even tried setting it to Navmesh walking on tick, and it still just says "Walking".

#

I've been trying to enable it to see the performance difference between that and normal walking, but neither profiling or this changes when I set it to NavMeshWalking.

📎 unknown.png
manic cobalt
#

I had to set it in the component as well as on begin play of the ai to get it to work

pine steeple
#

the CMC will force back to Walking under certain conditions aswell

#

i had to override the CMC and fix it

pallid mica
#

Is there a way to have a "Simple Parallel" but for non-task nodes? Seems lacking

#

I basically have multiple BehaviorTrees that, based on the State of the AI, will be used.
Inside of each of those, there is some generic logic for moving around and what not, that slightly differs.
Now I need to have some more logic that needs to run at the same time, but there are delays in there, so I need both branches of the tree to run without waiting on each other.

#

Guess I could split the trees up even more -_-

uneven junco
#

I'm working on a possibly novel AI tool but would like some help on deciding whether and how it can be useful. I find "AI" in UE4 always refers to direct gameplay and that is what behavior trees and EQS solves. What I'm missing in UE4 is AI in the form of logical reasoning, where as a designer/programmer you prepare rules for the game world in the form of: some parametrized facts let you derive other parametrized facts. So for example if you hurt an NPC's friend, that NPC will be angry at you. In symbolic form that could be written as IsAngry(NPC, You) is derivable from Hurt(You, OtherNPC) + IsFriend(NPC, OtherNPC) both being true, or
IsAngry(NPC, You) := Hurt(You, OtherNPC), IsFriend(NPC, OtherNPC).
^ this is very much the Prolog programming language for those who are familiar. The right hand side facts Hurt and IsFriend can be either directly stored in a knowledge base or outputs of other rules.

What I'm working on is a graph editor where a designer-programmer makes graphs to represent those rules and I provide a solver that takes whatever values you assign to graph variables and tries to fill in any unassigned variables. The properties of rules feed into other rules would be present as well, so there would be multiple graphs that define why someone could be angry at you. It could be because you hurt his friend, but also because you stole his wares.

Back to the realm of games, this tool would be aimed at making NPC decisions and provide details that can communicate to the player how the decision was made. Or those details can be stored for later and have later gameplay impact. But for example, it can be fed into dialogue like "[NPC John] is [Angry] at you, because you hit his friend [NPC Mark] with a [Legendary Baseball Bat of Power] on [December 14th]", but expressed in a more natural way.

#

I wonder if any game is doing stuff like this yet. The only example I can think of myself is Animal Crossing because you can easily spot the variables in the dialogue, but I'm sure there must be more. What games/game tools/research tools are out there that already do this?

tight bluff
#

do ai tasks resets variables automatically?

uneven junco
#

BT task nodes?

tight bluff
#

yes the ones that u use on trees

uneven junco
#

if you have variables on the task node classes, they don't reset

#

but multiple characters will use the same task node instance

#

which is why variables should be stored on blackboards instead

tight bluff
#

oh so for example if i use arrays in a task, i always have to clear them before the task succeds?

uneven junco
#

if its a member variable of the task node class, then definitely

#

if its just an array in function scope then no

tight bluff
#

im not sure i know the difference between them, let me check a sec

#

its not inside a function so i guess i have to clear them everytime

#

just one more thing, if do navmesh volume works on planes as terrain? i mean is it able to calculate a path on planes? cuz if i press P the area does not turn green...

uneven junco
#

yes, it works on any geometry that is flat enough, has collision primitives and blocks the right collision channel

#

and the component has CanEverAffectNavigation checked

lament hemlock
#

Does anyone know how to access UCrowdFollowingComponent::SetCrowdAvoidanceQuality? I have an ACharacter class and set the AIControllerClass to DetourCrowdAIController, but I can't work out how to get access to any of it's functions?

uneven junco
#

Yes, it will be a component of DetourCrowdAIController so accessible by casting the AIController's GetPathFollowingComponent

#

UCrowdFollowingComponent* CrowdFollow = Cast<UCrowdFollowingComponent>(MyAIController->GetPathFollowingComponent());

#

@lament hemlock

lament hemlock
#

@uneven junco Thank you very much, that was what I was looking for.

ocean wren
#

Zhikang: The sims does a lot of that kind of rule-based stuff. Have a look at GDC AI videos for what games have used.

#

I remember Richard Evans talking about huge rule-bases in Sims 3.

forest brook
#

Hey, OnLinkMoveStarted's description mentions path following will NOT update velocity until FinishUsingCustomLink() is called on it
but even if its true, it continues to update velocity, and FinishUsingCustomLink is never called...
Am i missing something or the description is wrong

strong plover
#

@uneven junco I think you could effectively achieve this same sort of concept with a mini-faction type system (on a per npc, or per small social group level), that uses a reputation point setup, where you propagate a comprehensive list of rules, set point weights to them, and then store any rule infractions into the npc's character. From there, you'd have to cycle the list and create clever dialogue covers (using the animal crossing example, you'd do something like (if 50 or more months) "It's been TOO LONG!" instead of "when you don't show your face for over 147 months"), and the like. What you're asking for isn't exactly tricky, per se... as much as it is time consuming/tedious.

#

Stardew valley did a very simplified version of this sort of thing, using point weights on items gifted, on a per npc basis. If you were to take that sort of idea, and explode it, you could essentially at the very least emulate something similar to what you're talking about.

thorny jay
#

Hi everyone. Is there a way to disable EQS warnings? My server logs start to get very large after a day or two of uptime due to constant warnings about queries overrunning

uneven junco
#

Exactly I want to build a system to take out that tedium, while you can already script everything with one-off code or dialogue trees. Stardew Valley's NPCs are a bit too simple for my tastes, Animal Crossing is more like it except they lean too much on random blatter being cute (it suits that game, just wouldn't translate well to more serious settings)

#

@strong plover Do you know of any games with really interesting tech driving the dialogue? Emulating behavior by simplifying it is what I'm trying to avoid, I'm very interested in the subject of how can we achieve robust dialogue generation, like even theoretical stuff that just hasn't been implemented or put to the test yet.

#

I am very interested in how Bioware did it! Is that how they did things in Mass Effect or Dragon Age? both?

uneven junco
#

DA: Origins is one of my favorite games because it had such good dialogue and branching quest lines

#

Please do ramble 🙂

#

Alright I will when I'm more awake then, thanks! 🙂

strong plover
#

@uneven junco There's a wide variety of ways you could tackle it, but ultimately, you'll have to "simplify" to an extent, for the sake of time, sanity, and performance. The system I described above could works simply as a concept, but would take a LARGE amount of time to properly design and implement. While I'd love to wrap my brain around it at the level you are, the level of complexity it would actually call for is much more in-depth than the time I have available permits. I do wish you the absolute best of luck quenching that curiosity, though! Would love to read about progress when you've got the ball rolling

uneven junco
#

Thanks for the encouragement. :) Yeah I will have to simplify at one point, probably to not layer experimental stuff onto experimental stuff and find out too late that its missing a key feature at the core. I'm looking forward to share progress actually because I might have a proof of concept soon that lets you make rules as graphs and perform queries from a knowledge base.

dense stone
#

How can l set my ai Hand follow LOcation of my character player?

wise iris
#

FloatingPawnMovement (defaultpawn) doesn't seem to respect accel/decel with MoveTo commands, is this a known limitation?

#

Bascially these

#

Unanswered since 2016 & 2018 🇫

#

This...sorta works? But there's a really weird acceleration curve where it almost doesn't accelerate at all for a few seconds in the beginning.

📎 unknown.png
pseudo breach
#

Has anyone ever worked with AI navigating a moving platform? Something like the deck of a ship. As I understand it, traditional navmesh won't work.

dusky lodge
#

Navmesh can be generated dynamically around an Actor.

pine steeple
#

yeah you want Nav Invokers

pseudo breach
#

Oh, awesome. I'll look I to that! Thanks guys

wanton oyster
#

for some reason my ai stopped seeing things at all and in debug mode i see nothing

#

my behavior tree is working fine but the aiperception doesnt seem to be seeing anything and im not sure what could be wrong

strong plover
#

Anyone have any good reads for AI navigation to feel more natural, using EQS? I'm about to start working out the best course of action to get AI to path up stairs in a straight fashion, despite their destination being in a diagonal location from start, and other fun pretend-to-be-human stuff.

wanton oyster
ocean wren
#

@uneven junco There's an interesting rule based approach that Elan Ruskin? at Valve did for Left4Dead, they used it for doing the dialogue, but its basically a contextual rule-based system. Was interesting because they reduced everything to interval arithmatic (basically floating point number checks). There was a presentation out on the net at some point. I think he did a GDC talk about it. If you search for Dialogue Left4Dead. Honestly, this isn't a million miles off a Utility architecture, but it is a bit more boolean than that. If you search for Dave Marks book "behavioural mathematics" you'll get the idea of a Utility architecture. Or look for Kevin Dill's presentations at GDC. I quite like the Valve approach because it worked well for narrative designers and was pretty quick to prototype, also because it was text based, the editing involved was pretty simple.

strong plover
#

https://www.youtube.com/watch?v=tAbBID3N64A is the video you're thinking of, I believe

YouTube
GDC
AI-driven Dynamic Dialog through Fuzzy Pattern Matching

In this classic GDC 2012 session, programmer Elan Ruskin shows a simple, uniform mechanism made for the Left 4 Dead series for tracking thousands of facts and possibilities, allowing intelligent characters to remember history, cascade from special to general cases, and select the optimal dialog, script, behavior, or animation for every situation...

▶ Play video
#

Was a great watch tbh

ocean wren
#

Looks right yeah.

uneven junco
#

Perfect, yes I remember L4D had lots of cool dialog during gameplay. Proocessing from "thousands of facts" from history is also what I want, really relevant thanks guys. I'll also look into Dave Mark and Kevin Dills work.

lyric flint
dense stone
#

L have create my ai character movement with blueprints.Now the problem is can l set the movement locations wothout need duplicate the actor?l mean copy paste actor on level but they will have different locations to go

flint trail
#

Happy New Year! 🎅 🎉

night relic
#

Is it possible to turn off the navmesh turning green?
Of course it's mandatory for debugging AI issues but the rest of the time is a pain in the ass

#

I mean, I eject while PIE and it automatically turns green, would like to avoid that

smoky summit
#

As in you don't want to see the navmesh?

night relic
#

@smoky summit yes

smoky summit
#

There is a show flag for navigation

#

You just turn that off

pine steeple
#

or just press P

slow peak
#

Hope this is the correct place to ask this, but I can't get navmeshes to work. The platform in the pic is little over 20 units tall, yet the navmesh with Agent Max Step Height of 50 can not step onto it. Internet just tells me "yeah increase max step height", but at 1000 it still doesn't want to step onto it, but starts stepping onto the house in the background.
Any ideas?

📎 unknown.png
#

nevermind, rebuilding geometry, saving, then switching to another level and coming back fixed it.

pastel gyro
#

it constantly flickers between the Task and the MoveTo

#

WAIT

#

NEVERMIND

#

I was never setting a variable so it wasn't moving anywhere

#

thus the flicker

#

problem solved

lyric flint
#

So my 'AI move to' successfully moves my character in the direction I want, however neither 'success' or 'fail' ever fires, instead the character keeps the movement input forever and just walks past the target point in the same direction infinitely

#

Odd thing is I have 'orient rotation to movement' on. I am doing a trial where I get my character to move A > B > C > D > E

#

He moves to A and when he is at A he faces the direction of B but does not change his velocity.

simple mantle
#

can anyone help me with a really simple issue? im making a side scroller game, and trying to make the AI aggro when the player steps on the appropriate platform. but there are gaps in the platform, so i tried to create a second nav mesh for the ai to use. however, only the first mob responds. when i reach the second mob, it stands still and doesnt recognize the new nav mesh

lyric flint
#

Any good tutorial for a basic AI ?

high moth
#

Sight

#

So I have a problem with AI focus

#

For whatever reason, instead keeping focus at player, it just takes somewhere very far and focus that one

#

The most interesting fact is that it never happened before

#

Nevermind, I accidentally disabled ticking on AIController

tropic breach
#

Is it best practice to put AI movement on the actual AI Pawn or in the AI Controller?

lament musk
#

Hey, I was thinking of trying to create a sand worm like enemy. Does anyone have an idea how to approach this. The sandworm would go under ground to relocate and come up again where the player is.

pine steeple
#

Smoke and mirrors @lament musk

#

we actually achieved that by having a special plane under the level, when the worm burrows, he hides himself, teleports to lower plane, and moves like normal, gets near target and burrows up, by teleporting to the position, showing its mesh and doing the unburrowing animation

lament musk
#

aahhhhhh @pine steeple

#

I get it!!

#

thanks so much :))

pine steeple
#

KISS, keep it simple stupid is my philosophy

#

you could go super complex, or go super simple and achieve the same result.

lament musk
#

I'm trying to make a low poly sand worm as an enemy, I just had no idea where to start but, that way seems like the best way. Wish I would of thought of that xD Also, love that philosophy

pine steeple
#

ah we have a big sandworm 😄

#

can see our sandworm there 😄

lament musk
#

That model looks amazing!!

high moth
#

Ok, yeah, I'm back

#

For whatever reason, BT, instead of switching to another node, just flicks on one

#

I don't really understand why

#

Enemy is valid in that case

rigid portal
lyric flint
#

Thx

rigid portal
#

I'm learning as well. There is very little. Most tuts are the same.

rigid portal
#

CodeLikeMe on YouTube has a lot of AI stuff.

thorny jay
#

Hi everyone. I have a bit of a pathfinding difficulty. I want my AI to be able to stand in tight ranks and columns, but the problem is that an AI trying to get to a position in a rear rank will attempt to force their way through the front rank and get stuck. RVO avoidance/detourcrowd won't help here as the problem is the front rank forms an impassable wall. I need the AI to actually run around the side of the rank to get to the back. Anyone know of a good way to handle this?

#

If there is an easy way to have AI already in position detect if an AI is trying to get past them and move aside for a moment to let them past, even better, but it seems like a more straight-forward solution for now to simply have AI take the long way around to get to the back

ocean wren
#

An easy option, is to sort your positions by distance, so basically make rear rank move to points behind the front rank

#

other easy options, is to turn off collision between units in the same group

#

RVO/Detour should push them apart so they don't penetrate too much, but having solid collisions is definitely going to cause issues.

summer axle
#

Any good recommendations on Behavior Tree videos or writeups?

grave fulcrum
#

@summer axle The Unreal Academy has AI content if you are looking to get started.

#

This is an AI controller. How can I intercept the move inputs being sent to my character from the AI controller?

📎 unknown.png
#

I have a move to location moving the character around, but, I wanted to be able to use the move inputs being sent. How are the move inputs being sent?

#

Am I just misunderstanding how this should work?

wanton oyster
#

I have a sequence for having my ai move to a random location every so often and I have a wait for 5-7 seconds because I dont want him to move to much. The problem I am having is I have a selector above it and goes to an attack sequence if the player is detected and it can take 7 seconds before that happens. Is there a way to force the wait to end or maybe a way to make a wait task that can be interrupted

#

maybe i can make my own wait with a .1s loop or something

wanton oyster
obtuse parrot
simple crest
#

you need to learn how to control task aborts in your behavior tree @wanton oyster

wanton oyster
#

can you control task aborts from services?

#

i have an aiperception that a service checks to see if the player is spotted and a decorator on the sequence for the patrol but it doesnt check until the sequence restarts which is after the wait

modest totem
#

i want to cast to my AI blue print. What object do i need to connect?

languid horizon
#

why do u want to cast your BP, if it's a super-class you have access to the same (and probably more) methods/variables.

modest totem
#

im bigginer 😦

#

what do u mean 😛

languid horizon
#

if you want to call a function, just search it (in the menu, I don't remember the official name), and it should be there as an option

tropic breach
#

BeginPlay() vs. OnPossess()....which is called first for AI?

pulsar jetty
crimson hornet
#

Hello, could someone save me please? I would need some resources to study about Behaviours trees and AI controllers for hundreds to thousands pawns. I tried it on my own, buts the performance is quite low. My current setup:
A building spawns units every few seconds and these units go to fight each other
Unit has CharacterMovementComponent (for easy networked movement)
Every unit has it's own AIcontroller
Every AI controller spawns it's own BT
BT searchs for other pawns and use MoveTo

With few of them it's ok. But once there is around 30 I drop into under 60FPS. I tried to profile it and what it seems is those BT are eating a lot of resources, but I don't know how to solve it. My go to google scenario was: "Process 1 BT with multiple blackboards" but with no luck so far.

Thanks for anything

pulsar jetty
#

any idea what im doing wrong here? i want to have the float from my "director" updated in the blackboard on tick; but it never gets updated even though i can use a breakpoint on the set value and it hits on the first frame

#

@crimson hornet blue print BT performance is at least 10x slower than c++ performance. maybe thats the problem

crimson hornet
#

Oh, ok, I can try to rewrite it into C++. Thanks

pulsar jetty
#

noone got an idea on why my float does not update at all? i mean there is no "finish execute" for a service huh?

crimson hornet
#

@pulsar jetty Probably a stupid question, but do you have the blackboard key set? Happens quite a lot to me.

pulsar jetty
pulsar jetty
#

no wait. that was not the issue wtf

pulsar jetty
#

what the heck is that?

forest adder
#

is it possible to parameterize the Acceptable Radius on a Move To actor in a behaviour tree?

#

as in... I want that to be a variable, not a static number

wanton oyster
#

can anyone tell me how i can make an ai ignore certain smart links? i have shorter characters that should use a longer path to get somewhere and they keep going for the closest smartlink they cant use

uneven junco
forest adder
uneven junco
#

It's my main issue with many of the out-of-the-box nodes, there's always that one parameter that you want to be more variable. 😄 In my case the acceptable radius had to be the maximum attack range of the weapon the character had equipped.

#

So ranged characters can stop walking once they are within 1000 range, whereas melee characters want to be at 100 range.

forest adder
#

I actually ended up solving differently by reversing the logic a bit. I used a line trace by channel to check visibility and Distance and set a book flag, then set a decorator on my attack node checking if that book was set (CanSeeEnemy?)

#

But it’s pretty performance heavy that way especially with lots of monsters doing that on tick

uneven junco
#

I can imagine, you can still spread the workload like only line trace once every 30 frames and not do all monsters at once

#

But custom MoveTo node will be more performant, since the pathing will use some overlap check anyway, might as well be the right value

forest adder
#

Is there an easy way to spread the workload or you mean just track it in a counter myself?

forest adder
pine steeple
#

i just do a distance check

#

a squared distance check is cheap

#

no trace needed

#

i have a bb key called InAttackRange

forest adder
simple crest
#

EQS

pine steeple
#

that is handled via Perception system

simple crest
#

the answer you actually want is use EQS to find a valid shoot position

pine steeple
#

EQS is ok if you want to move to a position, but it depends on the nature of the game

forest adder
#

Maybe I need to look at EQS again. We’re using that for our movement decisions

forest adder
#

Towers and core are static position. Player can move

forest adder
uneven junco
#

I haven't checked out EQS yet and but I should. I have a question myself now.

There's a nice quality of AIController->MoveToActor that it follows a moving actor. If you use the weapon range as overlap radius, then until the character gets into 'weapon range' of the moving target, he will keep updating how to reach the target. If you use EQS, can you still achieve that? Or would you have to make sure to recalculate, for example the shooting position, yourself every few seconds?

#

Btw I definitely acknowledge that pathing towards an actor until you're within 1000 range is far from a strategic method. 😄

simple crest
#

actually if you're doing a tower defense with a lot of units I might worry about the performance impact of using EQS... it might be too slow. maybe you do want it to be "dumber" and just move towards the target and shoot once perception can see it

#

all EQS does is allow you to generate a set of "query positions" and score them by some means

#

the score can be affected by distance to target, distance to caller, line of sight obstructed, anything you can code

#

the naming of all the parts of EQS is super confusing when you first try it

uneven junco
#

Gotcha, and if you want to prevent having to repick locations the trick is to assign a higher score to locations that will remain relevant even as the target moves

simple crest
#

if I understand what you're asking, a simple "improvement" might be to ensure that a query position is always generated exactly on the shooting AI unit's position, and give it a bit of a score boost over other positions as long as it is still a valid shoot position - helping the AI "prefer" to stand in place and keep shooting from there. One annoying thing with basic EQS grids is that it generates a grid fixed around the AI by default, so sometimes the AI will keep moving left-right-left-right in place as the EQS regenerates constant new grids while he's in mid-movement. it doesn't snap to any world units or anything'

#

also for a tower defense it might instead be possible to use a subsystem or something similar to constantly and slowly generate and update sets of shared attack points, and then use EQS on each unit to score a limited set of attack points... that might not make sense unless you get into the systems a bit... not sure if it would be the best idea still either, I only deal with small unit counts in my projects

modest totem
#

Why when i am spawning ai from class it ignors moveto commend

#

it only works when ai see another ai or me

#

i am bigginer so sorry if this is not good "code"

languid horizon
#

@modest totem I think it's because you didn't specify the Behavior tree of the AI (on Spawn AI From Class node)

modest totem
#

i will try 😄

#

on my way to find how to use Behavior tree

#

😛

languid horizon
modest totem
#

oki

#

Thank u ❤️

#

just found that ai works the same with spawn actor

#

its just dont move. need to see me or other ghost

pastel gyro
#

Is it better to have one AI Controller/Behavior tree for all enemies or should I have a Ai Controller/Behavior trees for every unique enemy type?

pine steeple
#

share what you can

#

i have a single behaviour tree for basic enemies

#

and for special/boss enemies, they have there own treee

#

BUT i reuse trees, as you can run trees inside trees

#

@pastel gyro

pastel gyro
#

wah you can run trees inside trees?

#

tree-ception

pine steeple
#

yes so i split trees into unique things

#

like Move To Waypoint Tree

#

which i can use on all AI if i like

#

look at Run Subtree node

pastel gyro
#

gonna do that now. Thanks a lot

wise iris
#

Holy shit, I didn't know that

#

That makes BTs a whole lot more usable

vast sluice
#

I'm having a issue with navigation, basically the AI can choose a random spot to move to when it can't see the player, but for some reason if the player enters the path the AI is moving in/to and it sees the player but then just stands still and doesn't chase, Anyone know a fix?

frigid compass
#

Using the following method results in PathPoints containing points inside a dynamic obstacle. How can I prevent that from happening? I'm on 4.25

UNavigationSystemV1* NavigationSystem = FNavigationSystem::GetCurrent<UNavigationSystemV1>(GetWorld());
UNavigationPath* NavigationPath       = NavigationSystem->FindPathToLocationSynchronously(GetWorld(), StartingLocation, TargetLocation);
PathPoints = NavigationPath->PathPoints;

Blue debug spheres are the path points. I'm not sure what are the relevant factors for this to break so feel free to request as much info as needed

📎 Navigation_not_working.mp4
frigid compass
peak solstice
#

was there a change in how ai works in v26? previous stuff isnt working for basic moving around anymore

pine steeple
#

nope

frigid compass
#

See how most waypoints take the dynamic obstacle in mind, but the last one doesn't care about underlying area being navigable or not. What could be causing this? Is the desired target location supposed to be included on the path?

📎 Navigation_not_working_2.mp4
peak solstice
#

I plug in the basic AImoveto into the base thirdpersonchar, and it never moves, even though im positive ive set it up right

pine steeple
#

as long as its not on beginplay

#

it should be fine

frigid compass
#

@pine steeple any idea on my question? Am I giving so little info that you can't make any guesses? In that case, what data is missing?

cyan sigil
#

Hello AI experts. One problem I keep running into is that I have a squad of characters that all need to navigate to a particular area via EQS. However sometimes that area can be quite small. How can I ensure that they pick destination vectors that haven't already been chosen by another character in their squad?

echo lark
#

write manager which selects positions for all characters

cyan sigil
#

Write manager?

#

Would that live external to the behavior tree?

echo lark
#

yes

#

it might be behavior tree still

#

but it will manage multiple actors

#

instead of one

cyan sigil
#

Is there some example or article I can read about how to properly make an object that manages multiple character AIs at once?

#

Does it just run an algorithm and manually edit their blackboards?

echo lark
#

I honestly don't know about articles, never needed them

#

but pretty much yes

#

you create single object

#

which will reference "squad" of AIs

cyan sigil
#

I guess I could make a EQS filter that excludes vectors that already exist on other units' blackboards.

#

Checking their destination instead of their current position.

echo lark
#

yes

#

but you still should run it globally

#

not per AI

cyan sigil
#

When would I kick it off, then?

echo lark
#

that I don't know

#

don';t know your design (;

#

either way, the simplest and standard way to do it

#

is to created single object say SquadManager

#

which will reference all squad AI

#

it will find positions for all AIs within squad and write it to Blackboard

#

it may or may not tell AIs to go here

#

squad communication is broad topic

#

you usually do it trough some centralized object, since it is easier

cyan sigil
#

Got it. thanks.

echo lark
#

though I have seen implementation where AIs communicate by sending messages to each other, Ithough it's complicated to get it working correctly

pine steeple
#

SquadDirector FTW

near jetty
#

i use Commander

#

often 1 per faction

#

if only one faction then just 1

echo lark
#

really depends on game, I've stick to hierarchical command

near jetty
#

of course\

cyan sigil
#

Commander? Is that a plugin?

ocean wren
#

Just to chime in on the squad thing (having done it recently), take care that movement is basically a thorny issue in tight spaces. I'm an advocate of turning off solid collision entirely and using force penalty methods (seperation) to push squadmates apart. That way you never get any rigid blocking that really messes things up. Also, when determining where to move, make sure you assign furthest points to agents that are closest to them first.. basically do it in distance order, so you don't have a guy at the back wanting to path to the front.

#

And yes, having a central system to keep track of target positions is a key feature. I created components that designers could add to objects that added positions to features like doors and windows. That way the components could register movement position features (one at the top and bottom of a ladder for instance, or ones near a door as stacking-up positions). Then having a squad order system that executes a given move order coordinate the agents via a squad controller (squad members are part of a squad that issues orders, checks completion, implements ordering of particular movements etc)

#

Also, using points isn't a great idea in general. Prefer using "rails" as per Cryengine where you can.

#

Rails being basically walkable volumes that don't contain a blockage. Usually placed along walls parallel to the surface. See Cryengine docs.

flint trail
#

I miss your AI tutorials @ocean wren 😊

cyan sigil
#

@ocean wren Doesn't the nav volume of Unreal handle that already?

cyan sigil
#

In addition, is there an online course I can take to learn more concepts of AI? I have bits and pieces but a comprehensive one would be nice. I've seen a few about Machine Learning but I dont know if they apply to games too.

cyan sigil
#

I am watching a tutorial for how to make melee attacking characters and part of it doesn't seem right to me.

#

https://www.youtube.com/watch?v=nMSdoMvJFvY&list=PL4G2bSPE_8ulvuPbPGC7rThydK5pBdB9G&index=1

YouTube
Ryan Laley Games
Unreal Engine 4 Tutorial - Melee AI Part 5 - AI Attacking Continued

In this series we will be going through how to create a melee based AI enemy, and go through how to get a group of these enemies to attack you as a team, often seen in many third-person action/adventure games.

In Part 5 we continue work on getting our AI to attack us.

Support me on Patreon and get access to videos early, join our developer com...

▶ Play video
#

On the character Actor he puts an Attack function that makes the character animate (probably a stub)

#

Then he adds an Attack function on the AI Controller that calls Attack on the character.

#

Then he makes a Task that calls Attack on the AI Controller.

#

I guess why is there three steps when they could do two?

#

Task that calls Attack on the character? Or are tasks meant to only affect controllers?

#

I must be unclear when it's appropriate to add functionality to the AI controller as opposed to the Behavior Tree.

meager imp
#

if you had to program a suuuuuper simple AI, say, the red koopa from the first mario....
would you still use a behaviour tree with the blackboard or just wing it in a blueprint?

where do you draw the line?
just curious 👼

flint trail
#

@cyan sigil not everything you see in YouTube tutorials is correct or best way to do it. Just learn what you can and then make your own AI.

simple crest
#

Impossible to judge without seeing the whole picture but it sounds like very basic clean code principals... I.e. Limiting dependencies between multiple classes, avoiding spaghetti code, etc.

uneven junco
#

As for why the behavior tree task doesn't call Attack on the character directly, that would mean that that behavior tree node can only be used by one character class. I'm not sure if this is his reasoning but generally behavior trees contain logic that does not need to be restricted to one Character class so it's a waste to program it that way.

echo lark
# cyan sigil I must be unclear when it's appropriate to add functionality to the AI controlle...

https://www.youtube.com/watch?v=Qq_xX1JCreI&t=1152s

YouTube
GDC
AI Arborist: Proper Cultivation and Care for Your Behavior Trees

In this 2017 GDC talk, Bobby Anguelov, Mika Vehkala, and Ben Weber outline core principles to get the most out of your behavior trees while avoiding common issues.

Register for GDC: https://ubm.io/2yWXW38

Join the GDC mailing list: http://www.gdconf.com/subscribe

Follow GDC on Twitter: https://twitter.com/Official_GDC

GDC talks cover a rang...

▶ Play video
#

the simple answer is that BT is not for decision making

#

but for plan execution

#

if you think you BT is about to make decision break execution make decision like
"I'm shooting now. I'm hungry, break shooting and go search for food" that you should move it out of BT

#

BT should only flow in one direction and never cycle

cyan sigil
#

@echo lark I'm watching that video. It seems like Behavior Trees are meant to be standalone encapsulations of high-level plans? And the AI Controller picks what it wants to do?

echo lark
#

yes, that's one way of doing it

#

you can use state machine to select decision

#

or some utility based selection

cyan sigil
#

Remind me what Utility selection is? Is that when you evaluate all possibilities and do the one with the highest score?

echo lark
#

yes

errant basin
#

Hey guys, does someone know a good way to make traffic happen? im thinking about making navmesh modifiers on the side and in the middle of roads to prevent them from just going on the wrong side ect. but idk yet how im going to do trafficlights ect

echo lark
#

if I knew about that video sooner or actually cared to read that BT ia acyclic graph, that would save me shitload of time 😄

cyan sigil
#

I'm an amateur but my approach would be to create nodes and splines between the intersections, that represent paths the cars can follow.

#

Navmesh assumes the navigating entity can go in any direction at any time.

errant basin
cyan sigil
#

These are explicit paths that pawns can take, rather than ones derived from the navmesh. It's usually used for things like jump pads and ledges.

errant basin
#

so basicly i could use a nav link on a road to determ where it can go? and block navigation with collision/navmesh or?

errant basin
cyan sigil
#

I think you'd have your car prioritize following links instead of using the mesh. I don't know how complex you want your car AI to be.

#

Is this like GTA where cars will move normally but break traffic laws to avoid danger?

errant basin
#

something like that

#

basicly from point a to b and follow rules like traffic lights thats my first goal, whatever i do from then on, idk yet

cyan sigil
#

Okay let's assume that they will only follow explicit paths/splines/links for now.

#

As for traffic lights, they will need some way to inspect that there's a light nearby and wait for it to change when they get close.

#

You can have nodes on the path store a reference to traffic light objects for easy checking.

errant basin
#

i was planning to make a trigger box for the traffic lights, and when they get inside it and the traffic light is red/orange, they will have to stop, for the other cars behind it, basicly if something else with the tag "car" enters a trigger box infront of them, if a car enters it, they will also stop

#

or is that stupid?

errant basin
#

that way it would be faster to setup roads instead of making it all out of splines

#

or is that just lazy xD

cyan sigil
#

The reason Navmesh works is the assumption that a character on a particular polygon in the mesh can travel to any other part of that polygon, which may not be the case for a car. It also assumes they will take the shortest possible path, rather than obeying traffic laws like one-way streets and staying in a lane.

errant basin
#

hmm thats true

cyan sigil
#

I suppose you could mess with the navigation AI of your car to disallow any path that requires a turn that's too sharp.

#

You also need splines on roads anyway so the car understand which direction the road is travelling.

#

Cities: Skylines for example has their entire road system be splines that draws the road art/mesh around it.

errant basin
cyan sigil
#

So you already have nodes and splines?

errant basin
#

but that doesnt seperate right/left lanes

#

splines to draw meshes basicly, like a crossing of 3 ways, normal roads

cyan sigil
#

That's good. You can use the splines in your art too. You can try tweaking the car's AI to pick points that are adjacent to the spline on one side depending on the direction they are travelling.

errant basin
#

true! that sounds a like a good way!

#

so basicly what im thinking now, the AI will follow the spline points (always asuming its just one lane for now) and the next spline he has to move to, he will caculate whats there on the right so he has a point to move to without crossing the middle of the road

#

question is, how am i gonna let the AI decide how to drive from point a to b?

#

its not random driving around 😅

cyan sigil
#

Choosing final destination is separate from choosing the route, fortunately

#

Start with a single spline and get the vehicle to follow it back and forth with the behavior you want

errant basin
#

hmm

#

any youtube vid or tutorial about this?

cyan sigil
#

I don't have one. Sorry. 😦

errant basin
#

okay, then i gotta think about something, thank you for the starting point

#

maybe someone else will read this and have something

lyric flint
#

Hello so I've been following this tutorial and everything has been going smoothly so far, except I can't place a second path point, I can create one/duplicate the first one, but it doesn't show up anywhere and all I can see is "path point 0" but "path point 1" can't be seen, although it's supposed to show up inside the patrol path allowing me to move it https://youtu.be/eLI6TOXaG5k

YouTube
Ryan Laley Games
Unreal Engine 4 Tutorial - AI - Part 4 Patrolling NPC

In this episode I show you how to make a NPC patrol a route; travelling from point to point.

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vast sluice
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I'm having a issue with navigation, basically the AI can choose a random spot to move to when it can't see the player, but for some reason if the player enters the path the AI is moving in/to and it sees the player but then just stands still and doesn't chase, Anyone know a fix?

errant basin
vast sluice
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No the AI has to chase the player if it sees it

cyan sigil
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Anywhere I can get a bunch of sample EQS Contexts in C++ to examine?

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I am attempting to make a simple one for "Retrieve an actor from the current querier's blackboard"

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Hmm, it looks like you can't actually configure any variables on an EQS. So how would I accomplish the above if I want to be able to configure the blackboard key?

errant basin
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i dont know any about c++, sorry 😬

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i got an idea for my ai tho:
use splines and navmesh
basicly whenever a car gets close to a spline point, he will move towards it
to sperate lanes, ill make a navmesh mod with a entery value
for outside of the road, ill make a more expensive navmesh, but the spline will make sure they cant getout but if there is some kind of reason (escape or something) they could

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for traficing lights ect, ill just have colisions on all the road entries and switch between affects nav mesh or nah

worn shore
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Heya, anyone have little experience with navigation settings? I set navigation to dynamic and added agent component. All working fine with my character - AI avoid me as dynamic obstacle.

But when i add same option (can affect navigation) to AI character all area around NPC becomes red and AI character struggle to move.

cyan sigil
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Maybe the AI character sees itself as an obstacle

fresh remnant
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Is there a way to slow down behavior node transitions so that we can debug it easier using the in-game AI debugger view(' key)? States switch really fast and just flash on the screen

misty wharf
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Logging or breakpoints could help with that

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You could for example create a decorator which just logs when entered and put it on the nodes you want to look at

cold trout
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worth mentioning is the fact you can breakpoint nodes in the BT and step backwards to see what behavior led to it

solid bear
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I have problem.

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My Enemies(AI) can see my character through walls if was spawned more than 1 enemy.

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1 Enemy: all is working fine. 2 or more Enemies: they can see my character through walls.

fresh remnant
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@cold trout oh did not know u can step backwards!

cold trout
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yeh its sweet, the camera doesnt jump back to it tho as it you might expect, so it can be easy to miss what its doing

young copper
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Hi guys

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Is there someone know how to do an ai like granny from the popular game granny

verbal violet
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Hi folks,

What is best practice to pass some values from some config file to behavior tree decorators/tasks/services ?
I need that for some distances for example, maybe some cooldowns?
Some values which i can expose to game designer and he can tweak that?

Earlier I made some custom tasks or decorators and get values from controlled pawn's BP ?
but i think that is not good, too many casts too many couples things...

young copper
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Is there someone know how to do an ai like granny from the popular game granny

pine steeple
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@verbal violet you would need to do that yourself, i exposed curve tables which i can tweak for different params

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you can access these easily in C++ and BP

verbal violet
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@pine steeple but how to do that? That require some custom task or decorator? There is no some other way, like using gameplay tags, where ask some in decorator or set in task...

pine steeple
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i made all custom tasks, decorators and services

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even my own move task

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which supports more features

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even made custom Gameplay Tag decorators cause the built in one doesnt handle aborting

verbal violet
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Ok, i will consider that, thanks. I did similar thing but all my parameters is in BP...

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That's wrong because cousing many cast and additional couplings

pine steeple
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i try to keep things generic

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i have a few special cased stuff

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but that is it

verbal violet
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👍

simple crest
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@solid bear sounds like shared blackboard keys

cyan sigil
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How do you configure Named Params when doing EQS? Is it only in blueprint?

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Can you have a named param come from a blackboard?

pine steeple
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named param can be setfrom anywhere

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🤷

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Behaviour Tree, BP and C++

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just fine

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@cyan sigil not sure what you mean

cyan sigil
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Oh! Very nice. I was only looking at the code.

cyan sigil
# pine steeple <@!101389465238409216> not sure what you mean

Ah, I found that. So now I have another question. Rather than extracting the Min and Max values from blackboard, I already have an Object in the blackboard that I'd like to retrieve values from when the EQS occurs. Is that possible or reasonable?

pine steeple
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would need to write your on EQS Task/Service

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to pull that object and extract the values

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or make a service to set BB values to those values

cyan sigil
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I am torn, at the moment. I did a dive into how values are set and there's a robust object called the UAIDataProvider I could use.

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I'd have to sublcass it and have it retrieve a value from a Query Context instead of query params.

cyan sigil
cyan sigil
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So I think it's possible I can do this. I'd have to subclass UAIDataProvider to extract values from the Ability. But this also means that people besides me would be unable to use the blackboard to set up the query.

cyan sigil
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I am comparing Decorator and Service, and I noticed that both can tick. Is the only difference that Decorator can stop the task it owns while Service cannot?

pulsar jetty
misty wharf
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afaict it's a cone from the direction where the AI is looking

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based on the degrees value for sight

solid bear
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I know.

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That is sounds not good.

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But now.

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All is working fine.

solid bear
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Hello, guys. I need your help.

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My AI don't sense damage.

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Any damage. I dunno why.

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Please, mention me. I can be AFK.

pulsar jetty
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enabled detect neutrals?

granite vault
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anyone knows how to prevent RVO AI from walking into walls?

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Without using RVO everything is fine and not even clipping through walls once.

pine steeple
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rvo is just velocity based

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it has no other checks apart from the pawn capsule blocking

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so you will have to make your own system

granite vault
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I see, no wonder it can even run through walls

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Detour Crowd Controller is weird too

pastel gyro
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if something in a sequence fails, does the sequence go back from the beggining?

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For example if the highlighted selector fails, the squence never reaches the other selector

📎 unknown.png
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the middle selector will always fail. the right most selector will always pass, but it never gets to it.

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ahhh it should be like this

cyan sigil
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Yeah. Sequence stops if a node fails. Selector stops if a node succeeds.

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I find it frustrating there is a default node to run a dynamic behavior but not one to specify a dynamic behavior. You need to write your own for that

solid bear
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@pulsar jetty
Maybe it's bug? I'm using 4.26.0.

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U are just enabling sense and this should work.

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But, nope.

meager imp
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If I need my AI to just move a character in a direction (no pathfinding, just hold a direction)... what would be the correct approach?
Doing this ends up in stutterstepping 😦

📎 unknown.png
pulsar jetty
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oh and you use "add movement input" instead of move to location

meager imp
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if I use move to location I need a navmesh and I am making a 2d platformer 😖
Can't I ask the AI to move without a path? just hold a direction?

uneven junco
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You could try MoveTo some location 10000 distance way and uncheck path finding

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Probably not the cleanest way to do it, and the task will continue for a long time so you basically have to abort it with a decorator 😄

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Or make your custom task call MoveTo (some faraway location without pathfinding) once every 10 seconds and Finish the task whenever you want

uneven junco
frail summit
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hi!

I have a couple of NPCs that I walk around via MoveToLocation on the AIController.
When they move in a pack, they tend to get stuck on each other, is there an event or something like that I could hook into?

shell socket
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hey, so this is probably a pretty dumb question, but I have a rabbit npc, and in MoveToLocation I want the pawn to hop over to it. I already have all the anims and all that, but how do I actually do that?

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also should clarify, the radius i have MoveToLocation set to is very small, to simulate the pawn jumping, I just have no idea how to physically make them jump up in the BP

frail summit
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@shell socket does your rabbit actually need to jump over anything?

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Otherwise just make it an animation

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would probably end up pretty hacky but I don't see how you could do it with just movetolocation

meager imp
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How are EQS queries meant to be used in 4.26?
I tried to add a Run EQS query node and it yells deprecated all over the place 😦

slim dome
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quick question, is there no way to change ai perception parameters during runtime? (Hearing Range, etc)
I hear that it is possible with the pawn sensing component, but that seems outdated and slower compared to ai perception from my understanding.

bleak gazelle
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Is there a way to set ExposeOnSpawn variables through SpawnAIFromClass?

worldly salmon
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Has anyone made a custom env query context here? I have some problems

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I want to use some volumes to mark some areas with different priorities, so that my AI is more willing to be able to go to the designated areas

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I think I may need a custom env query context to provide such a location set to compare with the generated points, but I don’t know how to do it, I don’t understand how to write this blueprint

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This idea came from this video https://www.youtube.com/watch?v=G8W7EQKBgcg&t=249s

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In this 2017 GDC session, Naughty Dog's Matthew Gallant explores the development process of Uncharted 4, and the lessons they learned about partitioning control of the AI between design and engineering.

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I imagined that this area has several priorities. For example, we divide it into ABC according to the priority from high to low.

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We use the lowest priority C to set a basic "battlefield". For example, we have multiple sentinels, and each sentinel will have a large area with priority C. We use a large box to represent it. In this way, monsters belonging to sentinel 1 only need to consider the position of sentinel 1.

In the area with priority C, there are several areas with priority B. We can assign different areas to different AIs, or multiple, and so on. There are also areas with priority B The area with priority A can also contain multiple

I imagine that we can use the EQS system to deal with it. But I don’t know how make the context blueprint. Can someone help me?

verbal violet
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Hi people,

is there any way to get something like "Input Axis" from AIController?

I find great tutorial for locomotion but for player, and it use Input Axis as some input parameters for animations, so i want to adapt and use same system for my enemies and npc.

https://www.youtube.com/watch?v=v0hB-GAEMuk&t=1927s&ab_channel=Filmstorm

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Join our Filmstorm Motion Library: https://www.patreon.com/filmstorm

Join us on Youtube Gaming and click join next to the like button:
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Unreal Marketplace Link - https://unrealengine.com/marketplace/open-world-animset
Get the Open World Animset today: https://gum.co/openwas

Part 2 of the Root Mot...

▶ Play video
#

Also I'm not sure it is right approach?
I suppose i can't use MoveTo task in BT with this, instead that i need some "axis input" where enemy should go, left/ rigt one axis and fwd / bkwd second axis?

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Here everything smooth and well blended so i want something similar to achieve

meager imp
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addMovementInput is as close as I got to what you ask @verbal violet

verbal violet
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@meager imp that move pawn in some direction? I need reverse thing, something like MoveTo task which actually not move pawn just provide me information where pawn SHOULD move

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task which mimic input controller

pastel gyro
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how do you make an Actor blackboard variable?

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I'd rather store this actor i'm targetting rather constantly recasting

cold trout
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same for vectors

solar bronze
blazing stirrup
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Hello,

does someone know an easy way to let a crowd of NPC's form a certain shape? Like an army of Soldiers getting in formation (like in a strategy game) or just pedestrians coming together and gather in groups, forming a Letter or a Logo. The Best way would be if I wouldn't have to set every single goal for every NPC but could command them all together, so I can use different numbers and a large quantity of people, also different shapes at will.

Im working with Blueprints only.

Thank you and have a great Day everyone!

maiden plume
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Hi yeah I get this message on the Set Value as Bool. But everything checks out. What's going on?

📎 unknown.png
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can someone help please?

shell socket
maiden plume
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DW It works now. Connected Get Blackboard Target Node to As ThirdPersonCharacter by mistake.

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bruh

dapper summit
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Less how specifically to do something, and more how to approach something. I'm adding AI to my game and want them to move towards a player when within an arbitrary range of the player, my issue is that I don't want to have lots of AI down the line that are all checking if a player is in range, especially if there were multiple players and having to check them all.

The only idea that I have thought of so far is to "split" the world into grids. Each grid would have an array of enemy objects which are the enemies present in that grid. When the player moves into another grid, it "turns off" the grids it has left and "turns on" the grid and adjacent grids that it is going into, and the world tells the enemies within the now "off" grids to stop checking the distance to the player, and the "on" grids to start checking.

I'm asking before I implement as I'm sure there's a more efficient way to do this. Thanks :D

cold trout
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@blazing stirrup off the top of my head (never done it) give all npcs a target actor, call it group waypoint. In the waypoint have an array of points that kinda form a circle. Always set the npcs target location to the target actor at some index of its own in the point array

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Project point to navigation maybe

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Then you could swap out the target actor for different shapes

lyric flint
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so I've been using the same AnimBP and ThirdPersonCharacter for multiple things including parkour (vaulting with animations) pushing box mechanic (with push animation) and crouching, I've been using this since I didn't seem to have issues throughout following tutorial playlists- but then realized the NPC that used the same BP and thirdpersoncharacter was crouching, vaulting and pushing along with my character- but I continued because it wasn't a massive deal and I said I'd figure it out later, but up to the 10th in the AI tutorial series my character has the parkour mechanic working but he doesn't use the animations, I've been messing around for hours duplicating the character/animBP, renaming and such, but I'm truly at a point where I'm lost and don't know how to duplicate and have them separated without the game breaking and having a mess of technical issues.. please anyone here know what i can do?

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holy shit nvm, I'm so dumb- all I had to do was duplicate the blueprint and delete the added anim-graph

young copper
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is there/can you make a tutorial for First Person when the AI catches you it goes into a cinematic death scene (like a monster eating you example)

manic karma
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Hey there.

I have a character using a BTT_MoveTo node.

It's not taking the shortest path around obstacles. I think something is wrong with the pathfinding in the whole project, as the moveTo isn't dealing with obstacles very well at all

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Anyone have any idea what's going on?

pine steeple
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area classes do not prevent exiting

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only way to achieve that is the outer area classes deny pathing

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so you end up like this

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and the AI can only move inside that area

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but he can never cross the brown area

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though that is situation specific

wraith eagle
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@lyric flint A NavigationFilter would allow you to achieve that would it not? If the inner NavArea was valid for the character, but the outer NavArea was not?

atomic coral
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hey all ltns 🙂 trying to get up to speed on how AI/Animation work together in the modern day Unreal.. The person who put together my Anim Blueprint tied in a couple of custom event triggers, which work real nice inside the blueprint viewer... but.. how do i access them from somewhere? specifically, a Behavior Tree ?

warm dagger
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What are Pawn Actions (seem identical to BT Tasks) and when would I use one over a custom BT Task?

patent hornet
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@lyric flint that doesn't sound like a job for areas/filters

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if the area that can't be exited is easy to describe / is simple shape

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you can just mutate the target location, coerce it inside the box

night panther
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Looking for a little help

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how do I get the ai to move to a custom location. I have a door. I want him to go up to it and start working on it. I know how to make him go to random position just not a custom one. Using Behaviour Tree.

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I tried saving the location of the door as a public varibale

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Getting the service to save it as a vector

night panther
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like what is wrong with that

meager imp
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I have a problem with my query. I have a trace decorator thingy set to filter on my EQS and with the EQS testDummy works fine but when the AI runs it it tells me that the trace answered something janky.

I made it work before... How did I break this?

📎 unknown.png
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(setting it to scoreOnly works... but it used to work as a filter.... what did I break?)

nova prawn
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Hi, If i have a root class called Unit and have 3 Units of type Unit and a simple AI Tree which sets a random location can they all share the same behaviour tree? They are from the main Character class but I cannot find Run Behaviour Tree as a node when I try to add it to the Blueprint.
Thanks!

meager imp
rapid ridge
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In general what are things that should be logged in order to debug AI? I'm using the visual logger and I'm logging locations of actors and EQS locations but idk what else would be good to log

pine steeple
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anything that helps you visualize the AI

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what paths they took, why they took it, why did they attack, why did they jump down there, how did they die

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that kinda stuff

peak solstice
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is it better to use multiple small navmeshes or one big one?

toxic dawn
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try multiple and see what happens when your AI tries to cross into a different nav mesh

peak solstice
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yeah it seems to work fine with multiple meshes

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ive just heard offhand that big navmeshes can slow down the game

meager imp
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is EQS supposed to be janky in 4.26?
I am getting random crashes and weird query results and I don't know if I am messing up or this is still WIP 😖

mellow horizon
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dont use a huge navmesh

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its not gonna work

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properly

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from when i tried it

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this might be impossible, but is it possible to make an ai that mimics you, for ex if you jump the ai jump

meager imp
mellow horizon
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Yes

meager imp
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probably, yes
the janky way I am doing now my AI is to have a task that never finishes and during the tick do your stuff 😛

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less janky would be to use a service to look at the player and write the blackboard

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and subset of tasks that run depending on the blackboard values 🤔

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This is my new "go to location" task to not use pathfinding...
It is a good example

📎 unknown.png
midnight quartz
manic karma
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if you're spawning AI like me, then this messes things up completely

midnight quartz
midnight quartz
manic karma
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Turn off the auto destroy

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it's on by default, which was causing my problems

gritty haven
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anyone have a preferred method for AI Hearing Perception occlusion? Hearing perception is a settable radius around the AI Character, fair enough. But if the NPC is on the third floor of a building and the player is on the first, or the NPC is behind 3 walls, they shouldn't hear the player's footsteps etc. Visibility traces for blocking geometry seems too expensive.

manic karma
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I don't really think it would be that expensive if you ran the trace only on a perception update, or stimuli received

gritty haven
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I certainly can't think of an alternate solution

manic karma
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try it and see if it's too expensive

gritty haven
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I will. But there is an edge case where that might fail as well. AI is only a few feet away from player, but just around a corner. Line trace goes through two walls technically.

manic karma
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radius based activation

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small distance away = no trace

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does the hearing perception have 2 spheres?

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I seem to recall a falloff sphere?

gritty haven
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I only have seen one sphere but I know you can add more

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and small distance away = no trace seems to fail if they are 2 feet away with a thick wall between you and them lol

manic karma
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how does a corner equal two walls but a wall doesn't?

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are you thinking if the trace intersects the hollow area in the corner?

gritty haven
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yeah I was just imagining two wall meshes meeting to form a corner

manic karma
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I feel like the solution is obvious, and commonly documented

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but I can't think of what it is

gritty haven
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this is where I've been all day

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like this has got to be common af

midnight quartz
odd kite
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I have a feeling that the question I'm going to ask won't really be answered but here goes nothing. Does somebody know how to have an AI enemy acknowledge a VR character because I've been trying to figure this mess out for a month and some change?

peak solstice
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so im setting all my nav meshes, and from time to time, ill get something like this on a flat space, with the nav mesh definitely covering it. not sure why it would not link there when the collisions are fine and nothings blocking it?

📎 unknown.png
meager imp
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I was having those problems and they went away when I removed a plugin. But then they started again, luckily I can move away from navmesh on my game 😬

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I am quite a rookie here too, so I am not sure what is going on 😦

abstract gorge
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Guys ive got a question, i wanna simulate a town where ais talk to eachother and interact and follow their own sheduel, i wanted to know when i will hit a bottleneck? would be 10000 possible? some people told me about level streaming and someone suggested that i create a 2d world for npc interactions adn the 3d world is just rendered around me, what are your thoughts on that

quaint hill
gritty haven
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@quaint hill thanks! That's a different check than pure distance?

quaint hill
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Yeap, navigation path will give you path which AI would take to player, it is quite good indicator IF player is close even if line trace fails.

edgy sierra
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Hello there ,I am currently doing a FindLookAtRotation for my AI for the focusing part of the player. I am having a weird bug where whenever the player gets close to the actual AI , the values of the FindLookAtRotation go crazy. The parameters of the FindLookAtRotation are:

First parameter: The muzzle socket of the gun
Second Parameter: The Spine_03 of my character.

https://streamable.com/ec0n5j

Streamable
LtBdLSjhe6.gif
▶ Play video
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Any solution to avoid this jittering ?

vague fjord
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So can anyone help me?

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What I’m trying to accomplish is an npc having like cone vision that the player can be in view of.

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But I’m new to unreal and I’m not used to a lot of the stuff in it.

thorny jay
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Hi everyone, I've got a really strange problem that I can't figure out the root cause for. Some of my AI see enemies just fine and engage them as expected, but some of them see enemies but don't add them to the HostileActors array in the perception component

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I did some logging and found that the enemy is registered in GetTeamAttitudeTowards, and that it correctly returns ETeamAttitude::Hostile

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But if I access GetAIPerceptionComponent()->GetHostileActors(Array), the array comes back empty

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All my AI use the same controller, so same perception component

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All use the same character class too

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They are identical

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It's just that some have an empty hostile actors array, and some don't. Any ideas on what could be causing this? I'm completely stumped

cosmic stag
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what exactly should SetFocus be used for? is focus just another term for the AIs rotation? atm im not using set focus at all, and handling changing the AIs rotation myself, and turning off bOrientationToMovement when i need to etc. Is SetFocus just supposed to be a simplified way around that or is there more to it?

edgy sierra
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Essentially what focus is doing is doing a rotation of the controller's rotation which is the AI pawn's rotation yeah.

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As of now you can do a SetRelativeLocation to the actual AI and achieve the same effect although SetFocus on the AIController has some more implications with the AI itself. (So it is not just 100% rotation code ) Because it has priority levels.

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So I assume that it will be related somewhat to AI code.

pine steeple
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Focus is really good actually

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i have a few levels of focus which i override based on priority

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i don't need to clear the lower focus either

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so when im finished with the higher priority focus, it will drop back down to the previous lower priority focus

cosmic stag
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oh cool, so you use it as a proxy for like a CurrentTarget variable?

sturdy iron
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@edgy sierra Well in this close distance it cant really do that. Your spine is literally inside the muzzle as I saw if not close to the AI

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Imo you can implement an option to either keep the distance with player via moving backwards

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or just draw a meele weapon when the distance is <= close combat that you can implement