gameplay-ai

[uneven cloud]

There are lots of resources that you can Google. It's an advanced architecture that is not necessary for most situations. It's also not easy to use, so I'd be very concerned if you need a tutorial for it.

No there is not.

[misty wharf]

I'm updating some of my path check code to make sure it uses hierarchial checks since it's faster... but is there ever any reason to not use hierarchial mode? 🤔

(Just for TestPathSync ie. checking if a path exists at all, not for actually getting a path)

Oh wait I just noticed it says "hierarchial mode ignores query filter"... guess that's what it is then...

And also that means I can't use it lol

[nimble smelt]

Is there a good way to see what a pawn with the character movement component is TRYING to do?

It's supposed to stop before it reaches something and, well, it isn't

So I gotta figure out if it's got a logic bug or it's just shitty at stopping even though it's trying

[potent stone]

It depends on what are you using to make your Pawn moving

[ruby granite]

how can i combine multiple arrays

or make it so anything spawned by an actor is a child actor

[rare ruin]

Append (they need to contain the same type)

[rare ruin]

SpawnActor -> Result -> AttachActor to Actor (result in target pin, self in Parent pin)

[ruby granite]

I just ended up grabbing 3 seperate "get all actors of class" and linking them to destroys

For simplicity

[dense owl]

Sounds terrible 😀

[ruby granite]

apparently all of undertales dialog is one giant switch case statement

[dense owl]

I’ve heard of this yeah.

[ruby granite]

@floral compass every line of dialog is just this

thousands of cases long

[dense owl]

Ofc, none of this is related to #gameplay-ai 😀

[ruby granite]

lol

true

[floral compass]

I know, I was just wondering why that comes up as justification in response to "Sounds terrible"

[ruby granite]

some of the best games out there are actually made terribly

[jaunty cairn]

guys I want to make a AI,he will always follow us. but when we look at it he'll stop,I couldnt find a good tutorial for that. can anyone help me? probably I'll set "ai move to" to our fps character but

[dense owl]

Depends how complex you want it. At its simplest you can use regular MoveTo, a line trace, cast and stop movement. Otherwise, see the video pinned here on Behaviour Trees

[jaunty cairn]

idk if it's a ad or not,but if you know lethal company Coil-Head I want to make something like that

[dense owl]

I don’t know it but what I said still applies.

[jaunty cairn]

but how? with PAWN sensing?

[dense owl]

AI perception

[jaunty cairn]

what should I add?

[dense owl]

You should watch that video I mentioned, it covers pretty much your exact use case

You’ll just need to modify the behaviour slightly

[jaunty cairn]

okey but which one?

[dense owl]

#gameplay-ai message

[jaunty cairn]

In the video, it is said that I need to add blackboard. but there is no need. Because artificial intelligence will have 2 behaviors, chasing and stopping

what can I add instead of this?

[dense owl]

Well if you use behaviour trees you need a blackboard. But you can also prly get this done with just AI perception

[jaunty cairn]

Im watching AI perception part...

[jaunty cairn]

ooh nvm,you mean no need to add these

but even in there it's shows blackboard

[oblique basin]

If your behaviour is that simple, you could just do a dot product between the player (character being chased) forward vector and the directional vector between the characters (ai location - player location). If the result is > for example .7, the player is "looking". You can adjust this value until you're happy with the results.

However, games are very rarely that simply so understanding and implementing BTs and AI perception early is a good idea

[jaunty cairn]

I made that, but how do I make pawn sensing infinite? he can't see me when I'm behind the wall...

[oblique basin]

You'd use a collision channel that the wall doesn't block. I think default is visibility which is generally everything in the world with visibility set to true.

It sounds like you should do a rudimentary AI course before jumping in. There are some basics you need to know before trying to make a functional game.

[jaunty cairn]

how can I turn that off

ok I made it

[mortal magnet]

Hey guys, have an issue with my AI, where the enemy after losing sight of my should go into seeking state, but instead its going to attacking state and following. You can see in the bottom right that the state is indeed Seeking, but in the behaviour tree its running Attacking State

[floral compass]

Inb4 another scolding about modeling state machines with behavior trees :°)

[mortal magnet]

lol is this bad?

[floral compass]

It makes it extremely hard to do what you're trying to do

But I think what you might want to do is look into interrupting that "Move ToTarget" node. That's what's keeping you stuck in that branch.

[mortal magnet]

@floral compass thank you! I will look at that move to target node

though state aborts though when interrupted

[dreamy surge]

I want to put a chat gpt learning program inside my game is this possy

Like can my character use chatgpt to learn and use things like scenexplain

I would think it would just need a plugin ?

[dense owl]

That’s a #generative-ai question

[uncut rune]

Different people different opinions. If the game is quite small and you are not planning or you are 100% sure this is not gonna evolve into 159 subtrees, then I would say if it works, it works. The problem most people are talking about is when you are working in team or on a bigger project, you start doing something like that, and then someone comes, tells you to change the system, and you are like, uhmm i have to write it all from the 0 if you want these changes. So it's really honestly up to you. Still good to know the good methods to approach.

[manic sphinx]

What's the most efficient way in to find the closest k actors of a certain class (or tag, whatever can be done most efficiently) from a certain point? I have to run a kNN algorithm for my AI, but I'd rather it didn't run in N^2 time

I'm new to UE5, but not to programming

[uncut rune]

probably use Sight Ai sense to detect actors and then in code make it to only sense specific class

[manic sphinx]

That sounds like it comes with a lot of overhead and probably updates it every time any AI goes in or out of sense range of another AI, though

I only need the 4-5 closest ones

[abstract yarrow]

Hey guys. I'm super stuck on this very final bug in my game. I'm having issues with the enemy AI stopping himself from chasing the player after only a few seconds. I'm not sure where in the code this bug is happening but I put a print statement on the OnSeePlayer sensing event and it shows when the enemy loses sight of the player. I'm also having a huge issue with the enemy not roaming anymore. My AI Move to node that's connected to a GetRandomReachablePointinRadius keeps failing

[uncut rune]

but what is the context?

[manic sphinx]

I should emphasize that I'm dealing with a very large number of actors.

[manic sphinx]

Think simple flocking/swarming behavior

[abstract yarrow]

This is my enemy BP

[uncut rune]

You have to change it so it will only LookForward when it has Target not set (make it as key), and, on the second branch, you dont have to put blackboard because if there are only 2, and first one will be true (has target, so it's not lookingforward), it will always choose 2nd selector.

[uncut rune]

Any videos or more details? I can't picture it

[manic sphinx]

https://youtu.be/V4f_1_r80RY

[uncut rune]

so you are trying to make formations basically?

[manic sphinx]

No, I'm implementing an agent-based flocking behavior where each bird reacts to the movement of its k nearest neighbors

so for k=4, for instance, the bird needs to check what it's 4 nearest neighbors are doing

[uncut rune]

so you need to study EQS

[manic sphinx]

The hard part is efficiently determining which birds are closest for 1000 or 10,000 birds

[manic sphinx]

I don't need EQS though. This should be some very simple calls. I don't need to worry about obstructions, I don't need to do anything special when a new object comes within range, etc.

I really just need to quickly find the 4 closest actors of a certain class

[uncut rune]

make collision spheres for each of bird with radius that you need for them to gather all actors from class in their collision range?

[manic sphinx]

That was my instinct, but I suspect it's rather expensive for the engine to track all of those collision spheres, and I wasn't sure if it's querying them at times other than when I use them.

[uncut rune]

i think it will be expensive no matter what since its a lot of numbers

[manic sphinx]

Yes, so the idea is to minimize that expense

[uncut rune]

try to ask in #mass

[manic sphinx]

Thanks!

[floral compass]

Sounds like you need some custom octree search algorithm, otherwise yeah mass or EQS

But kind of smells like premature optimization. Mass can probably handle that, maybe.

[uncut rune]

Did you fix it?

[abstract yarrow]

@uncut rune I'm sorry I'm slightly confused. I also I was trying to build out a test version of my game and it keeps failing for some reason.

But you're saying I shouldn't use the blackboard/behavior tree? I also have code in each branch

[uncut rune]

run game and look what the behavior tree is doing and if its getting stuck somewhere

[manic sphinx]

Yeah, Mass seems like it might be the way to go. Can you point me at docs for using octree search in Unreal Engine 5? I'm a little new to UE, but a veteran programmer.

[abstract yarrow]

He seems to be stuck at the chase player branch but it's telling me that he cant find the player

[floral compass]

I'm sure there's some octree implementation deep within the engine. But not sure whether that's exposed at all. Otherwise it would have to be custom built.

[floral compass]

Also there is a "CrowdAvoidance" thing in mass I believe? Might be worth a look, too

[uncut rune]

Read what I said in the first response. You don't need 2 decorators here. You need only one to check if it as target, if has no traget, it will lookaround, if has target will follow the target, if he has target, he wont look for target. You need only 1 decorator on 1 node and set them to self abort on key/value change.

[manic sphinx]

I have a custom algorithm determining the movement behavior of each actor based on the behavior of others. I just need to locate the k nearest neighbors.

Here's the paper I'm working off of, if you're interested.

[abstract yarrow]

I get what you're saying but I just dont know how to do that exactly. I followed a guide to get the AI to this point and I get what you mean about it only needing one decorator but I'm unsure how to set that up in this tree properly

[floral compass]

I got that. I meant the CrowdAvoidance thing might use something to detect neighbors. Sounds like it to me at least, just a shot in the dark

[manic sphinx]

Ohhh, you're saying open the source and see what CrowdAvoidance is doing?

[floral compass]

Yup!

[manic sphinx]

Ugh, was hoping this would be much more painless

I'll make a note to take a look

Thanks!

[uncut rune]

You need only 1 decortaor that will check if the blackboard key AttackTarget (for example), has value or is set. If the blackboar AttackTarget is set, then it will do the FollowPlayer branch. If it has not, if will look for target. So you only need to set decorator blackboard on one branch. Are you using AI senses or how do you set the target for the ai?

or I see that you have boolean there? how do you set it?

[abstract yarrow]

Yeah I'm using AI Sensing and a HasSeenPlayer boolean

[uncut rune]

so just change HasSeenPlayer bolean, to the AttackTarget (actor type), and set the AttackTarget to be the actor (Player in that case), that it sensed.

and when it senses player, you set blackboard key to be the actor (player), and then it organically happens that if it has target, it will attack it, and when it loses target or has not (yet), it will do the look around*

[uneven cloud]

How big is the N? Most of the time that kind of thing isn't actually going to cause performance problems.

[manic sphinx]

Ideally, about 10,000

But this is also something I'd like to call as often as possible

So for any number, it's important to be efficient

[uneven cloud]

You're doing BOIDS, right? I recommend actually using the built-in version and not have them be actors.

[manic sphinx]

Not sure I can implement the rules I want in Niagara. Not using the BOIDS algorithm.

Is the Boids algorithm editable in Niagara? Can actors be stateful in it?

Er, can particles be stateful, rather

[uneven cloud]

I'm not sure. It's heavily tunable though. 10k actors alone is going to be really heavy performance wise. You could optionally look at using Mass and using a spatial data structure to get the nearest. An Octree or a quadtree.

[potent loom]

yes

you need to use HLSL though

[manic sphinx]

HLSL?

[potent loom]

the shader language

same one you'd use to write a shader in unreal

[manic sphinx]

Ahh, I don't know how to write shaders.

[potent loom]

there's not really a direct way to do it with niagara alone then, boids is state free though

[manic sphinx]

Can you recommend a starter for HLSL assuming I know C-style coding?

[uncut rune]

Would it be clever to have different AIControllers for computer/enemy units and for the real player? What i'm thinking that I will have couple of things that are in common, but computer ai will have some things different and I guess it would be easier to implement that?

[floral compass]

How would an AIController be used with a player?

[uncut rune]

For a base unit behavior so if the units are idle for example, they need to sometimes alone decide that they will attack if the enemy comes near them, so they don't get 1 shoted for free if the player is not looking. Basically something like auto-agro, that could also be switched on and off. Something like ''I'm ready to attack if enemy comes''. Does it make sense?

[floral compass]

Oh, for an RTS or something right?
Off the top of my hat I would use AIControllers for everything. The player would just not have an avatar in the game (aside from their mouse maybe). Units controlled by the player would just have much, much simpler AI. Actually, it could be so simple you might not need any AI classes at all.

[uncut rune]

Yeah I'm still thinking how to implement that, the simpliest and most clean what I'm coming to is to have 2 different AiControllers, probably with some copy pasted behaviors for both. That is why I want to make the AI simplier for the player, and at the same time I'm not sure if it's better to put ''behavior'' like if target is set then do: attack and this I guess I should do on Event Tick or with While? loop? That would make it also 2 different approaches for ''the same'' thing for computer and for the player, if you understand me. (player would use blueprints, while computer behavioral trees for the same thing).

maybe I'm actually misthinking AIControllers with behavioral trees??

I can have the same AIController but different behavioral trees for player and different for computer? That would be the point?

[floral compass]

Yeah I think this is what's happening. You can have all differences in the BT, provided your requirements fit the flow of BTs.

And depending on the required complexity of your AI too

[uncut rune]

Do I remember correctly do I set Behavioral tree in the blueprint of the actor?

so it uses that tree i specified?

[floral compass]

On the AI Controller's BTComponent

Your actors should never interface with any AI code, ideally

[uncut rune]

hmm, so would I need to make switch in the AiController for different classes to use different trees?

this is the way?

[floral compass]

Many ways to do that

Can start BTs arbitrarily at runtime too

It depends

I do GOAP-lite and run a BT based on the selected action

[uncut rune]

Hmm, I guess in my case as I have 6-8 different units, where there are 3-4 types that would behave different, i would just create 4 behavioral trees and set them with switch based on class (just thinking out loud). Do you have any better ideas?

I guess there is no easy anserw 😄

all depends as I'm thinking about it

I will just have to decide and go with something

there is even a way to probably make 1 behavioral tree, but to check if something is ''warrior or archer'' and then choose that behavioral tree path, right?

or it's not really the ''good'' aproach?

because that would work, are there any nos?

[floral compass]

Nah don't clutter your tree with irrelevant stuff.

Keep it simple

[uncut rune]

so would I go with different decorators or different behavioral trees for different kind of units?

[floral compass]

I think for RTS units you can probably get away with just BTs.

You can do it per unit, why not. Depends on the complexity.

[uncut rune]

I might be overthinking it with ''how different'' i wnat to make it for each unit, but I guess it's gonna almost all the same just different parameters which will be easy provided by each unit. And I would fit that in 1 behavioral tree.
So the only ''last'' thing that Im trying to make more clear is to separate computer units ai from player ''ai aka behavioral trees" would be to make 2 different behavioral trees and keep it simple.

[floral compass]

Again, not even sure you'll need any AI for player units

Since the player's telling them what to do

[uncut rune]

It's just easier for my head to imagine the attack, follow in the behavioral tree than inthe blue prints?

yeah but they need to keep attacking while having target

do I make it on tick then?

since I would need to have while loop (while target is set do)

and I would set the target for each unit by clicking with right button on the neemy unit

so what I was thinking I would just make it set state Attacking in behavioral tree and let it run in loop

at the same time I had idea that I would set bool to ''InAttackMode", and if the 1 target dies, and the bool is still set to true, it would look for the target next to it 😄

and it seemed right to do it with behavioral trees

[floral compass]

Putting states in BTs is a bad time

Check the pinned messages, you'll get a better idea of it

[uncut rune]

i watched them all 2 times 😄

[floral compass]

Huh

[uncut rune]

i don't get this concept of states

like what is the state in my example? xd

[floral compass]

You mentioned AttackState

[uncut rune]

yeah

[floral compass]

You don't wanna do that

[uncut rune]

i could set it by right clicking on enemy, and setting off by clicking anything else, then everything else would run

how else would I do it?

or are you saying that i should not use behavioral tree for the mechanic im trying to implement and just to do it in while loop / on tick?

or maybe even by timer? and invalidate timer when clicking somewhere else

[floral compass]

I'm saying you shouldn't try to model state machine behavior with a behavior tree

[uncut rune]

and state machine in my case is which part?

AttackState? like the behavior behind it that will do: AttackTarget, FollowTarget on the loop?

this whole thing should be done in blue print?

[dense owl]

State machine is a tool

[floral compass]

The behavior itself is fine for BTs I think
I just don't think you'll want to do the selection of which behavior to run in BTs

But again, depends!

[uncut rune]

maybe I'm calling my Attacking branch as AttackingState just wrongly?

😄

[floral compass]

Depends on what you call your other branches :^)

And how you do the selection

Because BTs are static priority
If you can't definitely say that there is a static priority to your behaviors then it can be tough to implement

[uncut rune]

if no target WaitForTargetToComeCloser xD, if target set (by player, or came into), GoAttack

so basically Idle and Attacking

[floral compass]

Well that can work
But it's rarely that simple

[uncut rune]

and GoAttack would be something like: FollowTarget, AttackTarget(dealdmg), maybe 1 more branch with ThrowSpell (with cooldown), and that's it

and maybe some units would have something like counter that if AttackTarget finished succesfulyl 3 times, then the next attack will be ''pro'' 😄

which I think it's similiar to the example from Epic Games where each time it went patroling, the hunger was increased by 0.1 and when reached 1 it had to go anjd look for food

[floral compass]

Try it and report back how it goes :p

[uncut rune]

and I can picture it beeing done with the behavioral trees, maybe Im wrong 😄

will report for sure ! 😄

[nova prawn]

Hi not sure what Im doing wrong here but my enemy is not moving at all.

I have assigned an AIController to this enemy and using a AIMoveTo node to move them but it always returns fail. Can anyone help please? 🙂

[cyan sigil]

Does the map have a Nav Bounds?

[nova prawn]

Yep

[cyan sigil]

Can you show us?

[cyan sigil]

Is that the blueprint you're using? It's using its own location as the destination.

[nova prawn]

Circled the enemy for ease 🙂

Isnt it getting the player cahracters location on BeginPLay?

[cyan sigil]

Ah, it's just a sphere? Does it have a Character Movement Component? Is it marked as Static?

See how the nav mesh makes a hole under the enemy? that means the enemy's sphere component is marked as Static indicating it will never move.

[nova prawn]

Ohh ok never realised that I,ll check the Static Mesh settings.

[cyan sigil]

And does your character have a Movement Component to actually perform the move?

[nova prawn]

Yep so its set to Movable and has a Character Movement Component

can see why im a bit puzzled as to whats going on.

[floral compass]

Looks to me like the sphere doesn't actually have a valid path to navigate
Uncheck "Can Ever Affect Navigation" on the actor to test

[nova prawn]

it is unchecked

[floral compass]

Uncheck it on the SM too

Or everywhere

It's affecting the navmesh somehow

[nova prawn]

Ok would this make it move to player character location ?

I have unchecked all the boxes there was 1 checked for Affect Navigation

so i,ll test again.

Nope no movement still

[floral compass]

Let's see the navmesh?

[floral compass]

Huh

[nova prawn]

Its showing the sphere is not "cutting" out the navmesh now.

[floral compass]

Well we've ruled that out

[nova prawn]

Thanks for the help 🙂

[floral compass]

Is your player actually valid when you call that move to node?

[nova prawn]

I tried this to check

[floral compass]

Do a print string if its not valid

[nova prawn]

You read my mind i updated it 🙂

The Player Is Not Valid does not print out

[floral compass]

Is the actor actually possessed by an AIController?

[floral compass]

Hmm

I'm out of ideas then 😄

[nova prawn]

Its very weird.

XD

Do i have to post a location in the AIMoveTo node or can you just use an actor ?

[floral compass]

I think it prefers the actor if you provide one

[nova prawn]

ah ok thank you

well i got an print out from the exec pin

[floral compass]

Now? Why not before? :S

[nova prawn]

this prints out the player character outliner name so it knows that.

[floral compass]

Oh ok

[nova prawn]

So it has the player actor which i assume means it knows where the player character is.

[floral compass]

What you could also try is to run that not on begin play but like 1 frame later

I think there's a delay by 1 frame node

[nova prawn]

Ok i,ll add a 2 second delay after Begin Play, (I thought about the Delay Until next Tick node)

ok with a delay node of 2s I get the print out of "Player is located" after 2 seconds but no movement.

[floral compass]

🧐

I'm done, off to bed 😄

[nova prawn]

lol thanks for the help nn sleep well ! 🙂

[dense owl]

If you want to properly troubleshoot AI, use the Visual Logger

[nova prawn]

Ok i found out what was causing my issue not sure why though when I disabled gravity on the Character Movement component (Because its a ball levitating in the air) it would not move anywhere but when I enabled Gravity it worked. I am not sure if the Character Movement Component MUST have GRavity Enabled for AIMoveTo to function or if because its a levitating ball it has no contact with the Navmesh as its effectively not on the ground (Bit like Dodgems they have to be touching the electrical roof to move)

I am not sure if this is right though as this would mean that to create a AI Move To flying enemy you would have to sit something on a box and set visibility of the box to hidden in game and then the box would do all the moving for the Enemy on top of it. Maybe someone can shed some light on this please. 🙂

[misty wharf]

If it's using CMC you would probably need to set its movement mode to flying, if it's on walking it most likely requires ground

Also using a Character as a ball seems kinda strange, it seems just a regular pawn with floating pawn movement would work better for that

[nova prawn]

I thought about using a Actor for the floating enemy because it seemed to fit, but I was unable to use AIMoveTo node with Actor are you able to use that with Pawn class?

[nova prawn]

This was the issue I h ad to set the CMC to flying and it worked, For testing purposes I,ll try to use it in Pawn Class too.

Thanks!

[misty wharf]

I think AIMoveTo probably requires a pawn, since actors can't be possessed by ai controllers, but pawns can

[nova prawn]

I,ve not had much experience with these Simple Move To nodes they sound very easy to use but for some reason im managing to mess it up xD

Do i need to add a CMC to a Pawn to make it move through the AIMoveTo nodes?

[misty wharf]

CMC only works on Characters, try using floating pawn movement instead

[nova prawn]

wow i never even knew that component existed 😮

Ok added that and added 250 to Velocity on X Axis Checked Can Fly and no movement

Sorry Im being so dumb here Im sure it,s not normally this hard.

[misty wharf]

I wouldn't worry about it, these are sometimes kinda complex

[nova prawn]

Im almostr tempted to look on the marketplace for a asset to see if i can reverse engineer it and see how others have done it am struggling to find up to date info on it. 🙂

Aha! a friend sent me this https://www.youtube.com/watch?v=j_Y-Tkb3YJM&ab_channel=UnrealEngineLearning

[floral compass]

I mean, something has to be messed up aside from the AI stuff
Have you tried using a behavior tree with the MoveTo task?

[nova prawn]

I have used the behaviour tree before with Perception Components and done a simple chase, patrol search and roam freely ai system before.

I thought if i wanted to create a game similar to Gauntlet all i need basically is a if player in range chase them

So i thought a Behaviour Tree might be overkill for something as simple as that.

[floral compass]

So try a 1 node behavior tree with MoveTo and see if that works. At least that way we could rule out a few things

It might be, but at this point I would just troubleshoot the problem

Because I don't see why what you did wouldn't work

[nova prawn]

Did you see i found out why the CMC Component wasnt working.

[floral compass]

No, I was sleeping 😛

[nova prawn]

Ok i found out what was causing my issue not sure why though when I disabled gravity on the Character Movement component (Because its a ball levitating in the air) it would not move anywhere but when I enabled Gravity it worked. I am not sure if the Character Movement Component MUST have GRavity Enabled for AIMoveTo to function or if because its a levitating ball it has no contact with the Navmesh as its effectively not on the ground (Bit like Dodgems they have to be touching the electrical roof to move)

[floral compass]

Huh

Interesting

[nova prawn]

I had to change the movement mode to Flying on the CMC for it to work

[floral compass]

I avoid Character anything like the plague, another reason to keep doing so!

[nova prawn]

So with this in mind someone suggested maybe a Pawn with a Floating Movement Component might work better so now having issues with that

Just learning stuff and troubleshooting at least with all these issues its more likely to stick in my head for future projects lol

[floral compass]

Yeah, try a BT with a MoveTo node. If it doesn't work at least we can rule out that it's not a problem with the AIMoveTo node

[nova prawn]

So am trying to copy the Character + CMC move to random location using a Pawn and AIMoveTo with a Floating Movement Component.

Ok have learned a few things. 😄 I understand better now whats happening.

[fierce sparrow]

can anyone suggest how to get past this initial module setup to try to get the state tree component classes usable in cpp?

[north oriole]

does anyone how to know in c++ if a vector blackboard key is unset?i see that when unset it has a magical large value, but do i really have to compare with it to see if it's set?

[floral compass]

You need "AIModule"

[floral compass]

There should be "IsSet" functions on the blackboard

I mean you can also just do this with the Blackboard decorator

[fierce sparrow]

Thank you so much

[fierce sparrow]

do I just regenerate the visual studio files and reopen? Still not able to add state tree component classes

[floral compass]

With Rider you don't really need to, but yes
Might be some Rider fuckery, try code completion instead maybe

[fierce sparrow]

idk, can't get it working off a cpp fps template

include both state tree plugins, first thing is go add the modules, close rebuild etc

[floral compass]

Oh, wait a sec

You're trying to subclass UStateTree?

[fierce sparrow]

yea UStateTreeComponent I think

[floral compass]

Sorry about that, I got it confused with BehaviorTree

For the component you need GameplayStateTreeModule

[fierce sparrow]

I have that one too

StateTreeModule, GameplayStateTreeModule, and AIModule

[floral compass]

What happens if you just include #include "Components/StateTreeComponent.h" ?

And then build?

[fierce sparrow]

include it in the build.cs?

I'll try it

[floral compass]

No, in a cpp file

Or rather in a .h file

[fierce sparrow]

its greyed out

[floral compass]

Yeah now build

[fierce sparrow]

interesting progress

[floral compass]

Okay, I think Rider was still generating VS files maybe?

[fierce sparrow]

but doesn't have schema and such

lemme see

[floral compass]

Newer versions do that automatically

[fierce sparrow]

So I just need to hide includes somewhere in the project?

didn't think that I needed to do that after installing the module

idk tried it from scratch in 5.3 too, I'm doing something wrong. Started new cpp FPS template, added the two state tree plugins, then closed everything. Built CS project files, opened rider, added the 3 modules to the build.cs

unless I'm just failing to understand that yes it's necessary to still have the #include StateTreeComponent.h and StateTreeComponentSchema.h in addition to adding the modules.

[floral compass]

Which version of Rider are you on?

[fierce sparrow]

2023.3.3

If I remove the includes I lose the functionality to add the classes, is that expected?

Am I supposed to just have the includes somewhere in the project or was that a workaround to testing?

[floral compass]

No, that's bonkers, sounds like Rider fuckery to me

[misty wharf]

🤔

Works for me

[floral compass]

Same

[misty wharf]

Without having to put random includes in there

Make sure you've opened the project from the .uproject file and not the .sln

I think some of this stuff doesn't work so well if you use the .sln

[fierce sparrow]

Hmm yea opening it correctly from uproject using rider

[misty wharf]

If you've been using Rider for a while, I would try clearing the caches for it... sometimes they get kinda wonky for some reason and it causes random erratic issues

from File->Invalidate caches

[fierce sparrow]

Dang thanks but no improvement

[oak bridge]

Guys I made 2 supported agents, one is the walk and the other is fly, basically I just set a nav proxy to fly so that only who's fly can use that proxy to "jump" between 2 platforms but I dont know how to set my ai character to use that fly instead of walk

[light void]

Alright, hopefully that can help someone else, although it is the very basics of AI and I likely do not have the proper names I am open to correction if I am wrong in something. Also leaving the Draw.io file if someone want it.
I watched the first 3 videos of this tutorial serie by Ali Elzoheiry and I realized that I did not really understand the order in which things happened. What objects where linked and how they interacts. So I made the following diagrams to try and figure it out after finishing the 3rd video.
https://www.youtube.com/watch?v=-t3PbGRazKg&list=PLNwKK6OwH7eW1n49TW6-FmiZhqRn97cRy

Please correct me if I misunderstood but it helped me understand the order in which things call each others better and I hope this can help others as well.

[floral compass]

Are there any good resources on designing good, less formulaic AI? Less from a technical perspective and more from a design or abstract perspective.
Like for example, instead of stupidly going if attack then do X; if block then do Y; if heal then do Z maybe having a more abstract aggression concept that dictates the next actions? Or a mood or something. Anything in that direction?

[fluid summit]

If you've built something simple like..chess or something like that, and you want to build simple AI for it, is it useful at all to use the builtin UE AI tools? Behavior trees and such?

[rich pendant]

Would anyone know why AI would take strange almost winding paths when using the move to even if there's a clear straight path the take. The image is an example of the type of path it's taking.

Edit: It's because I had them set at dynamic obstacles.

Edit2 : Scratch that, it looks like it still does this just less often.

[uneven cloud]

I would recommend doing the AI with Blueprints course instead of that tutorial. From the look of it, the tutorial gives really bad advice.

[uneven cloud]

GDC

[light void]

Blueprint course? What is it?

[uneven cloud]

It's in the pinned messages

[sullen crater]

Hello, guys!
Please tell me why this decorator can give true if I’m not in the navmesh at all? Chose to find a path from the AI ​​to the player

And it triggers precisely when approaching a certain point (not zero coordinates)

[bitter citrus]

HI all!

I was watching an AI GDC talk and it mentioned some cool functionality that they did with their behavior trees, basically one-off "impulses" that they could shove in and out of the behavior tree at will based on different things (most likely pawn/controller feedback). I was wondering if anyone had any idea on a method for accomplishing this. I'm thinking of it basically like an abort but an abortion to a temporary BTT that's not always there.

[floral compass]

Dynamic behavior node? You can inject a subtree into a running tree

Never used it though

[bitter citrus]

I have never heard about those. So cool. Thank you !

[floral compass]

Yeah it's maybe the best feature of BehaviorTrees that StateTrees do not have (yet)
Aside from, you know, actually working

[bitter citrus]

Maybe UE6!

[devout cave]

I'm using the GenericTeamAgentInterface to distinguish between friendlies and hostiles - I wish to have my agents deal damage or heal allies based on situation, is the only way to keep checking GetTeamAttitudeTowards in my tasks for actors in range, or is there a better way to handle it? Maybe an equivalent to GetHostileActors?

[devout cave]

this maybe? #gameplay-ai message

[shut ridge]

Hi, I have a question, so the Env query system thinks there is no path to the location, but this is only because my character that is using the query is 600 units tall and the query therefore uses the actor's location as the centre, I think. How can I get it to use -300 as the centre?

[spring jetty]

Hey Any idea why would BehaviorTree execution stuck in RotateToFaceBBEntry ?

[floral compass]

Only thing I see is this line:

if (CalculateAngleDifferenceDot(PawnDirection, FocalPoint - AIController->GetPawn()->GetActorLocation()) >= PrecisionDot)

Play around with that Precision maybe?

[spring jetty]

He Doesn't rotate at all, what is this code anyway ? the precision that I can pass to the task ?

[spring jetty]

is it what's inside the FaceBB Task ?

[floral compass]

If there is no rotation at all I'd check whether your target is actually valid

[floral compass]

That's the success condition on tick

[spring jetty]

it is valid, I'm checking for the validity before moving.

[spring jetty]

of the task ?if so, how did you access the task code.

[floral compass]

I opened the project in my IDE and searched for "RotateToFaceBBEntry"

[spring jetty]

Okay thx, I found it too.

[keen spade]

I'm having an issue getting this loop to stop. My AI investigates but then never stops.

I've tried adding timers to time it out that also doesn't work.

Ideally the AI investigates for a bit then goes back to idle.

If its being called over and over that would reset the loop, and the timer. So then how is it being called? How do I make it not do that?

[floral compass]

On first glance I think the branch is being reselected over and over after 3 loops.
When the 3rd loop finishes, what is the "ActionState" in the blackboard set to? It should be "Investigate" right? In that case that branch will once again be selected. Since you're never changing the "ActionState" within that branch.

[keen spade]

True, the "TaskReturnToDefaultState" should change it, but it seems to never get there. I guess that makes sense tho if it doesn't get there it will re-call the whole thing into another 3 loop

[floral compass]

I mean one "fix" is really simple:
Use a sequence node and move your "ReturnToDefaultState" into that. The sequence would execute the selector in your image, and afterwards return to default

[keen spade]

so like this?

[keen spade]

Thanks let me run this

That worked!

[floral compass]

Well, you've just messed up the left part of your investigate branch tho

Because now your "Go to roughly where the sound was heard" will loop forever

What you want is:

Sequence
-> Selector
  -> Go to roughly where the sound was heard
  -> Test go to random
-> Sequence
  -> Wait
  -> Return to default

Because I assume you want to "return to default" regardless of which type of investigation behavior has been chosen

[keen spade]

Thanks, yeah I'm trying a few things. The first branch has a BB Condition where "is actor set" so that seems to trigger well enough and not loop forever.

[keen spade]

Thanks a lot for your help. This seems to be working as expected now. Really appreciate it!

[floral compass]

Sure, no problem 🙂

[light void]

Anyone's got a good tutorial on how to handle non repeating movements for a few NPC?
I want a bunch of NPC to randomly select amongst points of interests on the map and chose a route between their starting point and their targets. Issue is that if I just tell them to go there, they will but they're gonne "optimize" the route and all go the exact same path.

[keen spade]

Sounds pretty custom, not sure there's a tutorial for that. I'd look for a Patrol tutorial and add in random points in between. AI doesn't move very naturally, at least in my exp. Very much move to location, rotate, move to location w/o much blending between movements.

[misty wharf]

I do wonder what would be a good solution for this also. Pathing between A and B but allowing some inaccuracy in choosing the "best" path

The only way I can think of is having some system that tweaks navigation area costs between doing the navigation queries, or uses different navigation filters in the queries which have different costs... both those solutions would cause the pathing to be slightly different as a result

[floral compass]

At the same time you would also have to take into account that it makes little sense for an NPC to run through a monster-infested forest just because we tell them to have "variety" in their navigation

[light void]

I had a few ideas but I really don't know.
First one was to manually define a few stopping points at the entry of every passageway (since in my case it's travelling inside a mall), find whichever is the "perfect" point (closest to it) then randomly select a point from the nearby points. Then you would have plenty of inaccuracies. That would mean defining a bunch of preset corner points and figuring out how to do that.

[misty wharf]

Yeah I guess you could have some kind of "smart" navigation in a situation where it's like that

[light void]

It does, if you are making a game with dangerous monsters :p
I'm making a game in a mall with mostly friendly NPCs. NPCs are having their leasurly saturday afternoon shopping.

[misty wharf]

Eg. you know you want to get to a location that's on the third floor from the first floor, so you would then let the NPC choose randomly from nearby modes of transport to the third floor, for example an elevator or different escalators

In this kind of setup you wouldn't choose destinations to path to, but rather, you would choose the destination, and you would define objects that allow the npc to get to that destination, so the npc would then decide whether it needs to traverse through an object to get there or not

This could in theory be achieved also through just using nav query filters, for example if you have a choice between elevator and escalator, you could randomly pick a query filter that allows using one but not the other

[floral compass]

Like a chain of points of interest or smart objects
Have them stop at a map of the mall to check their path and so on

[misty wharf]

I had a slightly similar issue in my game where the npc's would always walk into the store and then into the nearest shelf in the same order... I just randomized the order to solve it lol

(it's a video rental store simulator of sorts)

[light void]

"Nav query filters" let me add that to the list of tutorial to learn.

[misty wharf]

essentially a query filter is just something that you can use to choose which nav areas are valid for the pathfinding query

it has a few other more advanced features also

[light void]

That actually look exactly what I need. Randomly affiliate them to different filter for each path of the map. I'm just worried if that is normal to have dozens of Navmesh or if I'm making a mistake in my understanding.

[misty wharf]

You can define them using different nav areas, I'm not sure whether there's any particular limitations to those other than not sure if there's an easy way to have nav areas overlap

[uncut rune]

If I want to have different behavior trees for different kind of units, but on one AIController I have to specify that logic in Event On Posses to switch BT based on class or any other specifier?

[floral compass]

I'm not sure about OnPossess, but anytime during or after BeginPlay works

Or you could just create blueprint AIController subclasses and change the BT reference in each of them

[uncut rune]

Great, Ill go with subclasses. Didn't check if it's possible.

[midnight scroll]

Are there any easy ways or delegates to detect when an AI is using a specific nav area?

[floral compass]

Trigger volumes might work instead

[midnight scroll]

Would prefer to do it without relying on overlap code. Physics area query stuff is insanely slow on some platforms.

[placid halo]

I was looking into the EQS code and it's somewhat tied to behavior trees. If I'm not using them, is it that worse to just pop a trigger volume when I need to and go through the hits myself?

[harsh storm]

You can run an EQS query devoid of BT's

[terse glen]

Hey all, I've since heard it isn't optimal to handle dialogue within a BT but I've implemented it now 😅
I've set a quest system up and basically once the quest is handed in the AI will move to a location I've specified
The problem I'm having is, the MoveTo doesn't work if its done after the EndDialogue task, but it does if i do it before the EndDialogue
I don't see any reason why a previous task should stop it from running?

[placid halo]

I'm not at all experienced with BTs, but did you try to add a "wait" after the MoveTo?

[terse glen]

Yeah that doesn't work either 😦

[dense owl]

We don’t know what you have in that end dialogue task. For all we know you forgot to put a finish execute success node

[terse glen]

I realised it's because it's calls a custom event which uses 'stop logic', sorry 😅

Can i run these two in parallel? At the moment EndDialogue executes after it's moved to the location

[uncut rune]

Need advice and feedback.

So I made this behavioral tree for my worker, and it works. I'm setting blackboard key WorkerState by clicking on Resource when unit is selected. When I click on the ground or anyewhere else, it's set to Idle. This is just prototype. I set this from PlayerController to AiController by interface.
I also have the same 'behavior' done in blueprints, and the behavior tree seems more clear to me what is happening. I can also add Tasks like Collect that will actually take out the resource from the node, and then deposit it to the building. Everything seems clear.

There is also function inside AiController, that looks for the closest building, but I think I might just put it into task at the end of the Collect sequence, so in case building got destroyed it will have task and a way to find it.

Are there any disadvantages in the future from this approach?

I guess it will be easy to make task to send info that something got collected so -1 from TargetResource and +1 to the amount in the playercontroller on contact with building?

[dense owl]

you could try a Simple Parallel

[misty wharf]

Overlaps are slow? 🤔 Which platforms is that?

[dense owl]

Switch ? 🙃

[misty wharf]

Tbh probably never gonna release anything on console but I was always under the impression overlaps were reasonably performant lol

[midnight scroll]

PS4 and XB1. Anything involving the physics system is a death sentence to your FPS.

[misty wharf]

Interesting

I'm using overlaps a lot for some stuff at the moment, mainly because it was less effort than setting up a system like djikstra/influence maps for it lol

but it's easy enough to replace if it was to ever become a problem

[midnight scroll]

To be fair we were optimizing a game with a ton of stuff going on in a game. But the overlap and trace queries, and things like physx vehicle movement and whatnot are stupid.

@misty wharfJust double checked. PS4 has line trace singles running anywhere from 30 to 250 microseconds. Not even the component moving but just the simple function call to update overlaps on components hits for 18 to 130 microseconds. It adds up really quick in a more complex game.

[floral compass]

Aside from misusing selectors as state machines. You'll run into issues if it gets more complex than that.
I also don't see why "Collect" and "Deposit" are separate sequences when they're clearly just one sequence. But I guess you could argue for readability?

[uncut rune]

Yeah so this is basically gonna be it for the worker. I might add something like so if it's set by player to ''search for xtyperesource'' it will go to the closest resource of that type and auto gather (sets target). It's gonna be pretty simple for the worker bt. I find it a little bit easier to program whole thing with behavior trees than with the blueprint. Are there any no no to this approach or is it ok in general?

[floral compass]

I mean BTs (selectors) are good at selecting behavior based on priority and recovering from failure with fallback behaviors, right? That's their whole thing.
In your BT above you're effectively suppressing that functionality by introducing a very manual selection mechanism (states). So now instead of selecting by priority automatically, you have to tell your BT what to select. Your BT logic is "leaking" outside of the BT. Now your AIController needs to know that your BT expects a certain "state" and has to explicitly tell the BT what to do. If you switch BTs or change it you're forced to adjust your AIController logic as well.

Your example is great because it also shows how redundant a "state" sometimes is. You have a "TargetResource" in your blackboard. Why not make the decorator select based on that? If we have a "TargetResource" then execute the "Gathering" branch, else "Idle". You can ditch the entire state logic in your BT and AIController.

If you really want to work with states I'd recommend using StateTree instead.

Ideally, you'll always have a priority of behaviors in mind when designing your BT. If you want manual control over what is executed, injecting subtrees or starting a new BT would likely be less spaghetti down the line.

[uncut rune]

That totally makes sense, I will follow your advice. I will check StateTree too.

[uncut rune]

Yeah, so basically I'm not trying to make really AI, but I want to force some kind of behavior that I want in my game and it makes sense for me to make it with behavior tree (it's easier to picture it and program step by step). As I said I have exact the same ''behavior'' that is written in blueprint, and it's more complicated than it should be 😄

[floral compass]

Yeah that's fine, I also think BTs can be really good for organization and modularity if done right.
But whenever you read the word "state" in a BT you should be very careful about what comes next.

It's like trying to go grocery shopping

But instead of the shopping cart you just take your entire car into the store

Works, but not what it's made for

[uncut rune]

ok 😄

[floral compass]

And likely will result in jail time

[uncut rune]

hahahaha, please nooo !

[light void]

Is it possible to replace the default pathfinding with some RRT based one?

[nimble smelt]

1. This condition is supposed to abort this tree when TargetActor is set.
2. TargetActor is set. (See BB keys on right)
3. The tree is not being aborted.
4. What the heck.

The AI starts in this patrol mode and CAN initially acquire a target. However, when it loses that target, it then breaks so it can no longer acquire any target

[dense owl]

Target Actor is set. why would it abort?

[nimble smelt]

I mistyped in the comment but not the actual condition, it aborts when TargetActor is NOT set

In any case, I kinda sorta figured this out? But the results are bizarre.

So "FindTarget" is what sets the TargetActor, and I put a check in there for when it's being called and TargetActor is already set. And it turns out that happens All The Time.

My current theory is that AI detection sorta "flickers" as it is gained and lost. My check for that continuing evaluates false on the right tree that's not in the picture, but when it gets over to the left tree, targetactor is immediately replaced on first run, and somehow that doesn't count as Value Changed for the condition?

It's a theory with a lot of holes in it, admittedly, but the behavior I'm seeing is pretty tough to explain

[dense owl]

are you using something like onTargetPerceptionUpdated by chance?

or how are you updating

[nimble smelt]

...Shit, lemme open up unreal and check

This is the part which confirms I'm still detecting the actor, in the right tree

And this is the detection function. BUT HOL UP

"IsValidTarget", from that second function, actually wraps a call to CheckTargetPerception, the SAME function from the first one!

[dense owl]

btw there's a built-in perceived actors generator on the EQS composite nodes.

[nimble smelt]

That last part is particularly confusing, because what it means in practice is that "FindTarget" is necessarily more strict than "CheckTargetPerception", since it WRAPS the core part of CheckTargetPerception

[dense owl]

if you end up having more than one target to perceive, or if you have issues with perception updating, that will save your skin^

[nimble smelt]

Eh, I'm not using EQS for this project. First because I think it still needs C++, second because I've just got hella custom logic in my AI systems so I've leaned toward custom solutions for most things, and second because I"d already written a lot of this before it was released so it kinda "missed the boat" on this release train, to mix metaphors

[dense owl]

it doesn't need cpp

not for something like that anyways

but fair enough, if your way works

[nimble smelt]

hmm there was a reason. Does it tie in with the navigation system?

[dense owl]

you can use it outside AI entirely if you want

EQS is very versatile

[nimble smelt]

But yeah this version is working. Well, notwithstanding whatever the hell race condition I'm running into now

Anyways I'm technically on vacation lol so I'm gonna see if I have any bright ideas over the trip. I actually "fixed" it for now with a hack where "FindTarget" checks whether the target is set and if it is, it forcably clears it again, so that the next tick it can "update" the field in a way the tree actually notices

And it works! Though in theory it makes the AI 2-3 ticks less responsive than it should be.

[dense owl]

enjoy your vacation

[celest python]

as long as it works with navmesh

yes

pathfinding is a func ptr that you can replace

that you need inheritance to do so... 😄

[safe harness]

can someone tell me how to make ai hit targets with things like grenades or artillery?
i know that i can predict projectile trajectory, im wondering how to use it for correcting aim of npcs
im pretty new to ai programming
you can write either here or pm me, i would be grateful for any tips

[misty wharf]

This kind of depends on how you need it to work. There is a node that can suggest a launch velocity for arced projectiles or such which you could probably use, but this will not take into account the velocity of the actor which would require a bit more complex logic if you want it to predict the movement

[light void]

Is it possible have multiple AI sight and define what the character will do depending on which sight is working?

[misty wharf]

If you mean multiple sight senses - yes, but you need multiple perception components, one per sight

This also means it will do twice the linetraces etc. so keep that in mind

[sage walrus]

Hey guys, how can I find a specific smart object to use? I've seen many tutorials, but they all use the "FindSmartObjects", and let a NPC interact with any smart object. However, I want to find a specific smart object to use, as my NPC has a reference to the actor that contains the SmartObjectComponent. However, I can't seem to find a way to get a slot handle with a specific object reference, neither identify a object from the "FindSmartObjects" result, as it does not return any actor reference.

[light void]

Any way to handle detection of particular parts of teh body? I want to know if a character can see the hand of the player.

After checking it seems these kind of functions were not available to Blueprint. Is it still the case?

[floral compass]

I guess you could do a line trace to the hand bone?

[spark locust]

it was just some version control dumbfoolery most likely so removed my question 😄

[languid shard]

does anyone know how to filter output in one generator by output of another one (using custom test class) in EQS?

[misty wharf]

I'm not sure if any of that is BP exposed, I recall you can do it via C++

[misty wharf]

With AI perception yes... in C++ you can override IAISightTargetInterface

[nova prawn]

Can someone tell me why when I spawn a AI Actor it doesnt move when the original Blueprint its based off works fine, I have Auto Possess set to when Spawned or Placed In World, The enemies are spawning in but they arent moving at all when the original ones do move.

The 2 circled in this image have moved to the player characters location upon start of the game

The others rotate to face the player character but dont move.

[rapid atlas]

Hey! I've been having an issue with getting AI to move in standalone vs in editor. In editor, the ai moves in all rooms with a dynamically generated navmesh/room. In standalone, the ai only moves in the first room generated, but subsequent rooms cause the AIMoveTo node to cycle failures. I am spawning these enemies after the room has been generated. Any help would be very much appreciated!

[nova prawn]

This is the code spawning enemies

[misty wharf]

Visual Logger would probably have more info on why they aren't moving

if they are rotating but not moving that suggests the logic is at least running

[nova prawn]

Its odd that the Blueprint they are based off work fine but the dynamically spawned ones dont

[nova prawn]

I must be doing something wrong because the logger shows nothing.Have never used this debugging tool before tbh

[misty wharf]

You have to first press Start for it to start logging

[nova prawn]

Ahh thanks 🙂

Not sure what im looking at though tbh so much info

can see all the AIControllers

[misty wharf]

any red bars would indicate errors of some variety

[nova prawn]

no red bars that i can see

in the Path Following it says Moving when its not so the game "thinks" its moving. (I guess)

[misty wharf]

Are the ones you've put into the level manually which work set to use flying also?

[nova prawn]

The ones i put in level are set to flying as well

[misty wharf]

If you're using BTs I'd check what's happening with those next

[nova prawn]

Im using the AiMoveTo node

[misty wharf]

Otherwise it seems it's trying to move but for some reason is unable to

[nova prawn]

Doesnt make any sense as to why manually placed BP,s work but spawned ones dont seem when the spawned ones are just duplicates of the manual one. XD

[misty wharf]

I would verify it's actually in the correct movement mode and not in walking mode

[hearty niche]

I have baked my world partition navmesh but it does not show up when I play my game, my npc does not move. What's happening here? I did get the actors to generate.

[nova prawn]

I even checked they are the same Z-Height as the manually placed ones.Capsule Collision is set to No Collision so that cant be stopping it from moving

[floral compass]

How did you "possess" the manually placed ones? Did you assign a controller in their Blueprint or did you do it in the scene?
Also, does your AI Controller automatically start the behavior tree?

Unlikely these are the issues, but they're common gotchas

[misty wharf]

This is just the default, not the actual one it's currently in

Also check the return value from the moveto node, I recall it might give a status code or something

[nova prawn]

In the Enemy BP

[floral compass]

Is that not the issue?

AIController?

Should that not be some BP_MyAIController or something?

[nova prawn]

Isnt that just the Basic AI Controller class instead of a user created one.

[floral compass]

Because by default AIController does not have any BehaviorTree assigned

[nova prawn]

the manual ones are using the same controller as that.

[misty wharf]

If your logic is all in the pawn then it doesn't really matter which ai controller

[nova prawn]

There is no behaviour tree for this

[floral compass]

Oh, gotcha, blueprints

[nova prawn]

Yup just using the simple AIMoveTo node

well not so simple it seems xD

[floral compass]

How do you call the AIMoveTo node again?

On BeginPlay?

[nova prawn]

Yes

[floral compass]

Ah sorry, got it now, missed it earlier

[nova prawn]

Begin Play -> Delay 2s -> AIMoveTo

thats all there is to the code.

[floral compass]

Really interesting

[nova prawn]

Ok lets see what status result outputs

[rapid atlas]

A thing of note is that the ai will start moving if I show or hide navigation via the console using "show Navigation"

[nova prawn]

Ok so it spawns an automatically resuilts in SUCCESS

The manual 2 do the same thing but then print out GOT YA when they reach the player

The spawned ones never print out GOT YA so they never reach the target

[harsh storm]

Haven't been following but make sure you ensure to change the possession behavior for the AIController to support this. In your pawn, search for spawn and change it to both

[nova prawn]

this?

[harsh storm]

By default, automatic AI possession only happens on placed.

[nova prawn]

Ohh on the controller not the pawn ?

[harsh storm]

No, that's the correct setting

Also, do it on possession, not BeginPlay

[floral compass]

Good point

[harsh storm]

Check the visual logger as well. Check logs in general.

[nova prawn]

I looked at the logs there was no red bars, I think if these were "ground" enemys it,ll probably work fine xD

I,ll make a custom AI Controller and then do the OnPossession instead of doing the AIMoveTo inside the pawn

[floral compass]

That is recommended anyway I think?
Pawns should be agnostic of their controllers. But depends on the game!

[nova prawn]

same thing they rotate to the player but not move.

OnPossessed

Ok odd... I used default blueprint and just added a cylinder mesh no changes to CMC and it all just works.

the cylinders all were converging on me, So it,s something to do with trying to do flying enemies, I might just use ground enemies and put "flying" enemies on top of an invisible box lol

[floral compass]

That's good to know

Although weird it would work for manually placed ones, then

[nova prawn]

Indeed bit puzzled to say the least.

[olive prism]

How i can activate a Task only when i have a true variable in my BPI Character?

I made a decorator that is looking at a bool type variable in my character in a decorator and then I made a task that I gave it what it has to do (nothing for now) but it doesn't stop the execution flow of the BT even if it is true

[misty wharf]

Maybe add a print to check what value the decorator is actually returning

[north oriole]

What is the difference between a nav modifier area class set to None, NavArea and NavArea_Default?

[misty wharf]

I don't recall for sure but if you look at the navmesh generation when you use those you should see the effect... None might've been effectively disabling the navmesh from that area

Otherwise you might need to use nav query filters for them to have any effect

[north oriole]

None seems to keep the default navmesh under the modifier, and the others as well. Only difference I found is that NavArea_Default seems to prevail over other modifiers and use the default navmesh under them as well

[narrow python]

Is there simple free flying navigation plugin?

[uneven cloud]

What do you mean it doesn't stop the execution flow?

[uneven cloud]

Have you tried looking on the marketplace?

[uneven cloud]

Area classes change the cost of pathfinding. None doesn't add an area class at all. AreaClass is the base class, which doesn't set the costs. NavArea_Default does actually set the cost.

[north oriole]

So in my case where I don't want the modifier to affect the navmesh at all None is the correct choice?

[olive prism]

Everything continues to execute normally, even if the decorator variable is set to true

[uneven cloud]

Why do you have a modifier that doesn't change the cost?

[uneven cloud]

Are you expecting it to abort what it's doing and do the new thing?

[north oriole]

Because at runtime it changes area class, there are times where I want it to have an Area Class which actually does something, and sometimes I want it to be "disabled" by having Area Class "None"

[uneven cloud]

That's fair. I'm not sure you can change it to be none at runtime, so you might have to use default.

[north oriole]

It would seem I can according to my experiments

[olive prism]

Yes, I want everything to stop being done to execute only the BTT of the Roll when the bool that the decorator observes, when it is set to false, continue executing all the rest of the BT

[uneven cloud]

Then you need to make it an observer abort. If you don't use C++, then you can only do that by using a blackboard key. You'll want to abort lower priority.

Also if it's the highest priority, then you need to move it all the way to the left.

[olive prism]

It is to the far left, but before the Wield Sword and before the Death.

Should I put a blackboard? how would it be?

Should I put a status?

I could do it

Thanks!!

[uncut rune]

Is there any other way so I don't have to use casting? Theoreticaly I already have resource reference in the blackboard value as actor but since it's set as actor and not exactly building I don't have access to these things without casting

[floral compass]

Depends. Why do you want to avoid casting?

[uncut rune]

Just for the avoiding sake, don't have good reason but I don't like casting unless it's inevitable

[floral compass]

Then it's inevitable 😄

[uncut rune]

Ok 😄

[uneven cloud]

AI only exists on the server. Having a Server RPC function is completely unnecessary. They also don't work for server owned actors.

To avoid casting you can you interfaces. If you used C++ classes, then casting isn't a problem at all.

[uncut rune]

This is event that is inside BP_Resource that I'm calling from the Task. Should I just make it normal function?

[uneven cloud]

Yes.

[uncut rune]

So anything that I call from Task, but the event itself is on the Actor, it will be called as server? That's briliant actually.

I try to use interfaces in every place, but I'm not able to get interface from the blackboard value.

[uneven cloud]

It's only players that can use client and server RPCs.

[uneven cloud]

If it's only being called from the BT, then it'll be on the server.

The AI controller and all of it's components only exist on the server.

[uncut rune]

I have 1 more idea but it doesn't really work and I'm not sure why 😄 I'm trying to call Get AIController, from the OwnerController or Pawn (of the unit), and in the Ai Controller, I actually have ResourceTarget variable, which I could get from, but Get AiController doesn't really cast to the owning unit?

this is In AiController of the unit that is usit this AI

[uneven cloud]

You need to cast to your AI controller type.

[uncut rune]

Okay, so in this case still takes casting. Got it!

[uneven cloud]

You need to cast anytime you want to access the things you added.

[uncut rune]

Thank you ❤️

[rapid atlas]

Could someone help me? In the viewport, my spawned ai moves in all dynamically generated rooms. In standalone, the ai moves in the first room generated, but in subsequent rooms the AI MoveTo node is executing, yet not moving. If I have enemies placed in a room then those will work, but spawned ai won't unless it's the first room. The ai will start moving if I show or hide navigation via the console using "show Navigation".

[uncut rune]

Check this in bp of your actor that you are spawning

[rapid atlas]

Yea that's set to world or spawned, spawning works in the first room, but not subsequent rooms when in the standalone game

[real arrow]

does anyone know if AI Perception works from a 3D perspective

oh, it just uses a line cast doesn't it, so it would work

[narrow mason]

Yes it does. But you may run into an issue where if the object location is behind cover, but some of the body is visible it still wouldn't see the object.

Don't know if it's fixed now but it used to be an issue with sight perception

[celest nebula]

I'm using shooting as a service and would like the interval to reflect an AI's rate at which they apply a firing input. Guessing that must be done via cpp but it feels jank since you'd essentially set a default interval that doesn't actually affect the node. Any suggestions?

Probably just need to think of shooting as a task then.

[uncut rune]

Im brainstorming one thing. Let's say I have a lot ostats like UnitRange and others, which I want to use in the tree behavior to check if unit is in that range of something. What is the best way to get that data from BP_Unit to AIController_Unit? It get's funnier the more data you have, or I don't get something? What is the simpliest way? Make interface that gets all the stats and use possesed pawn as reference for these stats ? So If I need something I just reference from possesed pawn, GetUnitRange and set it inside AIController?

[hot compass]

Learning agents big update and updated learning material: https://dev.epicgames.com/community/learning/courses/kRm/unreal-engine-learning-agents-5-4/MpeM/unreal-engine-what-s-new-in-learning-agents-5-4

[lunar cedar]

any idea what would prevent my AI from moving in a packaged build? in editor everything works as expected but in a packaged build the spawn points i have selected will spawn the ai correctly, but they will not move as if they have no nav mesh. the spawn points inside of the building work just fine though. this is all one large nav mesh (minus the little guy in the right corner) and im not sure if its related to world partition or whats going on

[languid shard]

are you sure you have navmesh built and see recastnavmesh actor in the outliner?

[lunar cedar]

i assume its built since ai can move around, just not in the big area. yes i see that

[lunar cedar]

resolved by turning on the regenerate upon load in the recast nav mesh, thank you!

[light void]

Alright, I was not happy with my NPCs line of sight that would rely on the AIsight which end up looking somewhere around the crotch area. Which mean that any random obstacle would stop it with line trace. Currently, it can now look at the hand (will change later. Wanted to check how precise it is).
How can I allow Line trace to go through ranslucent objects? And how can I allow it to go through certain objects I'm going to define manually because I don't think they should obstruct vision?
How could I make it so my own body will break the line trace?
And finally how can I optimize it? Currently it will be running on tick for all NPCs, so how can I do some fuckery to ensure only NPCs within a certain distance (That I can modify with a stealth variable) even have the opportunity to detect? So that NPC 200m away don't get a perception check to save on performances?

[misty wharf]

1. IAISightTargetInterface can be used to customize exactly how the sight sense checks are done.
2. To make the traces go through stuff you need to adjust the collision profiles just the same as with any other trace. You can configure the default trace channel used for sight checks in project settings, or if you have a custom line trace setup then yeah just change that. Overlap or Ignore should let the trace to pass through. Same with the player blocking it, configure it to block the trace channel you use
3. AI Perception has timeslicing for this purpose. I recall it also does a distance and sphere check of sorts to see if you're even in range

[light void]

1. Not enough. Or at least nobody has been able to explain to me how to. I need to check if particular bodyparts are visible, but as far as I know there is no way to attach a Stimuli to a particular bodypart. All stimulis are within the main body and target only at waist hight. Did not manage to change it and repeated attempt at asking around have only be met with "Use Line trace instead".
2. I'll check the trace channel thing, it's not something I know about. I'll look it up.
3. I wish I could make AI Perception check works, but I really didn't manage.

[misty wharf]

https://zomgmoz.tv/unreal/AI-Perception/IAISightTargetInterface

You just override the CanBeSeenFrom function and do your own linetraces, you can choose where to trace with your own logic etc.

If for some reason you can't get it to work, for #3 you can use similar methods as the perception system does to optimize

[light void]

I guess I'm not gonna escape diving into the C++ code editor for it if I want to make it work.

[misty wharf]

Not if you want to use AI perception unfortunately no :)

[light void]

How do I have to go to find these functions and open them with Visual studio?

[misty wharf]

You would need to make a new C++ base class for the actors where you want to use this

and have your BP actor inherit from that

[light void]

Got any good tutorial to get started with that? I know how to code, I just don't know where to get started with codes in UE5

[misty wharf]

Check the pins on #cpp

[safe harness]

i have seen that there is a lot of tutorials that do this by matching the velocity, but i need the projectile velocity to be static for things like grenade launchers
as for movement prediction, that is a separate thing and i already have some idea how to that

[sacred shale]

Is there a way to observe a specific enemy behavior tree in real time without the need for spawning in only one enemy? I want to see what one of my specific enemies are doing but I'm not sure which enemy it is observing

[dense owl]

Only way I I’ve found is by running the game and selecting that specific instance

[sacred shale]

If I click simulate and have that specific AI selected is that representative of that AI's behavior tree?

[dense owl]

Iirc, yes.

I would also open the AI debugger to make sure that AI is now the self

Then you can be certain

[prisma sun]

Hey,
I have a Pawn with a Sphere component (to detect enemies and create the range of the Unit)

I have an issue for Navigation, MoveTo etc.
This issue here is that the Sphere Size is added to the radius of the Actor/Pawn so when I do a move to there is a lot of issues. (Overlap is not well calculated because the sphere is already overlapping)

My sphere is having a custom channel for Collision

[misty wharf]

Interesting question... not sure if there's anything you can do really other than not use the actor overlap features of the MoveTos and such

[prisma sun]

Yes and in that case, recreate my own move to I guess and calculating the location

[prisma sun]

Or maybe there is a better way for AI detection, but I don't know if using AI perception is not overkill 😉

[misty wharf]

Depends on what you're doing. AI perception is a fairly straightforward system and I wouldn't worry about it being overkill unless you have some very specific requirements

[prisma sun]

I will problably have a lot of AI so I don't know about the performances on it but I can try with it

[misty wharf]

As long as you configure it correctly it's probably just fine

Ie. if your AIs need to only detect the player, make sure it's set up to only do that, which would reduce the number of line traces it needs to do quite significantly depending on number of AIs within distance

[prisma sun]

Its more like an RTS with auto AI detecting other AI

[misty wharf]

Well it all really depends on the numbers and you probably would need to test it to really find out. It does have time slicing by default which you can tweak, meaning it can limit how much time it will spend per frame doing sense tests

[lyric flint]

anyone know how I can ensure my AI doesn't jump over a sub tree in their main behavior tree

I think my AI is skipping over it or something

[misty wharf]

It won't jump over it unless there's some reason for it such as the sequence it's in failing

although it wouldn't really look like it just jumped past it in that case

[lyric flint]

it must be going thorugh sub tree super fast then

I think i might know whats happening, so I have this question probability thing and well it's super dynamic in that it's super hit or miss if it's actual does the question thing, I think issue is it's not doing a question so zipping through the sub tree and back to the main one

[lyric flint]

my issue at moment is it seems the AI is going from Moving to Table and going over to Paying

even though the Current Guest Journey does go to ordering

and as you can see theres a 60.0 second wait there yet it's not doing any of that for some reason, any help would be great cause it wasn't until I added in the paying and leave table on right it's started to play up

[dense owl]

Run the game, open the tree, click pause, step back and forth

Also if the center branch is skipping, it prly means that current guest journey is not equal to ordering

You can use the AI debugger at runtime (;) to see what the blackboard keys are currently set to

[trail python]

I'm having this excat same problem with the mass ai system right now. I'll try this tomorrow 😄

[coral mesa]

is there any discord which talks about making game AI from scratch?

[floral compass]

From scratch meaning using assembly?

Or custom tooling/models in UE?

[coral mesa]

C++ like making FSM from scratch

im making one in ECS architecture but not sure what to do where

[floral compass]

I mean as long as it's UE I don't see why you can't discuss that here

But ECS + FSM sounds... challenging... 😄

[coral mesa]

i did made one in the past

FSM in Unity

pretty sure can do one in Unreal in traditional OOP approach

but ECS making it a bit tricky

[floral compass]

Especially considering that there is already a very performant state machine in UE anyway

[coral mesa]

also even thinking whether i should use GOAP instead because ill design diverse ai system

for starters I would make a state

an enum integer or something

then always check. If same enum then ignore otherwise do OnEnter

that's FSM I can do but what if player input is there to override the behavior?

[floral compass]

At this point I'd recommend checking out StateTree instead

[coral mesa]

i would still use what's there already but im not sold on memory management side

actor system doesn't have a good memory management tho

[floral compass]

Not sure what you mean?

[coral mesa]

i mean memories aren't packed together

compared to ECS format

[floral compass]

What do you get out of making your state machine ECS then?

Especially when there is also an ECS system already built into UE

#mass

[coral mesa]

gotta iterate through 3000+ NPCs

[coral mesa]

very primitive tbh

used flecs from Github

[floral compass]

Hmm, well good luck, hope your implementation does the job!

[lyric flint]

So it is equal to ordering as it was working fine before

It's since I added the stuff to the right it then started skipping the central bit

[dense owl]

#gameplay-ai message

[coral mesa]

can you keep switching between Behavior Tree during runtime?

[floral compass]

Yes!

Although it might be better to inject BTs instead, not sure about the technicalities behind restarting an entire tree

Actually if someone knows what is better switching or injecting I'd appreciate some insights on this

[coral mesa]

think ill just give up for now and will go through this approach

already spent months on other stuffs

maybe something for future instead

[floral compass]

You mean your state machine?

[coral mesa]

yeah. Currently doing Hybrid approach to work on ECS

i can communicate between ECS and Actor system

now worried about performance. xD

however i still got another problem yet to solve

i got pathfinding working but no local avoidance

[floral compass]

#mass has it I believe? Not sure

[misty wharf]

I'm not sure if there's a big difference between switching and running subtrees... switching would potentially just set up a new blackboard and a few things like that could in theory have a very very minor performance difference

If you need to keep BB state, subtrees would probably be a simpler option

Although I'm not sure whether the BB would get reset if the switched BT has the same BB type

[floral compass]

Yeah currently I do a full switch, but so far no issues. Although injection seems wiser because it enables you to have like an archetype BT and then customize individual sub-behaviors

[light void]

What is the "clean" way to define a place NPCs need to move to? Do I create some sort of invisible actors and ask it to move to that actor?

[misty wharf]

That's what I would do at least. Seems like the simplest way to do it in a way that's also easy to modify

[random cedar]

Hello friends why the KI is running aways from his patrol system when i hit him in the -x direction?

Here all you need to now
event tick activated my handle movement
Handle movement activated the patrol system
also event begin play activated the patrol system

i think it must something in the "Event AnyDamage" because there i have an select that should be change the rotation of the ai in the direction of the player...

[haughty tide]

Is there a way to get the current cost of a location in the navmesh. ? I would like to influence the score of a generator by setting a low score for generated points that have been generated on top of nav_areas that are of high cost.

[gentle widget]

Good morning, I'm having some isses understanding behavior trees, was hoping someone could help me out a bit.

I have a custom node that just set the AI state (and an equivalent value as a BB key so I can control states with the tree), What I want to happen is the AI see's the player, does an action (in this case screams) and then proceeds to chase. I've tried playing with different variables to see what the outcome is as well as refactoring the tree (this is the latest spaghetti I've come up with) to try and make this work. I'm obviously not doing something right I just haven't been able to figure it out.

While in PIE the graph get's stuck in this state, the left tree for chase player executes a single frame and then returns to this state. The scream nodes should be setting the AI state to chasing, but it's getting stuck.

[floral compass]

What does the task SetAIState on the left do exactly? Which state does it set?

[gentle widget]

It's setting the enum state value on board the enemy actor and the blackboard key.

Here's the task

[gentle widget]

Maybe I misunderstood the question, it's setting the state to "Scream"

[floral compass]

Yeah that was the question 🙂
Then I understand, it's doing exactly what you designed it to do!
It's executing the "SetAIState" task which sets the current state to "Scream".
Then it moves to the next branch and checks if it can "ChasePlayer". According to your decorator, the state is not "Chasing", so that branch fails and it falls back to the rightmost branch.

[gentle widget]

I see. I think I understand. Let me see if I can fix that.

Thanks!@

[floral compass]

Just a general question: why do you feel you need to incorporate "states" into a behavior tree?

There's a different tool for exactly that: StateTree

[gentle widget]

If you're referring to the animation state tree, then it's mostly because I want different AI behavior based on the enemy state, so I needed to incorporate it one way or another anyways.

This is my first time trying to program AI so I'm sure theres a better way to go about it. Mostly just brute forcing my way through the engine until stuff works anyways lol

[floral compass]

No I'm referring to the more recent (geared for AI but not exclusive to AI) StateTree plugin that enables exactly what you're trying to describe!
https://dev.epicgames.com/documentation/en-us/unreal-engine/state-tree-in-unreal-engine?application_version=5.4

It's a common mistake to try and model a state machine inside of a behavior tree. BTs are definitely not designed to do that. They work very much with priority of behaviors instead of states that are switched at will 🙂

[gentle widget]

I did not know about this

Let me look into that, might be why I'm not getting the behavior I want.

[floral compass]

Although your example clearly has a priority, so BTs should work, too!

Just have to get rid of the states and restructure a bit :p

[gentle widget]

I'm still learning the blackboard and behavior tree's in Unreal, seems like everytime I turn around there's something new to learn lol

But state tree's look exactly like what I want. Hopefully I can figure out how to make it compatible with my c++ code, but I'm a bit less worried with that part.

I figured out how to do it in BT's lol

[floral compass]

StateTrees are quite compatible with C++, similarly to BTs
You can implement tasks conditions etc. all in C++ or BP 🙂

But since the plugin is relatively new it tends to be a bit buggy for advanced use cases

[gentle widget]

Looking at the quick start guide, it seems like I can program behaviors into this state tree as well. Would this replace the behavior tree?

[floral compass]

Nope, they're just two different ways to model AI.
One deals with states that are switched arbitrarily (StateTree)
One deals with behaviors that have a hierarchical priority (BehaviorTree)

Depends very much on what your use case is and what you're comfortable with. But considering many people try to use BTs like state machines I think the former might be more beginner friendly, maybe?

[dense owl]

State Trees more beginner friendly? Doubt

[floral compass]

True, that's the wrong wording

More attractive? I lack the vocabulary for this

[misty wharf]

State Trees could be more beginner friendly if the documentation was less confusing :P

[gentle widget]

State tree does seem like the way I might need to go. Not havinga defined flow for behavior that flip in and out of certain states when necessary is pretty much exactly what I want.

[digital spoke]

Hello everyone, could you tell me the modules and the CPP class to derive a task for the state tree?

[floral compass]

You say that now, but wait until you have 20 transitions across 5 different nested states and then tell me how you like StateTrees 😉

[dense owl]

If there were actual decent resources on it yeah

[misty wharf]

https://zomgmoz.tv/unreal/State-Tree/Custom-StateTree-tasks

[gentle widget]

Lmao well, I guess I'll have to cross that bridge when I get there.

My game has a single AI enemy, so I only have to worry about one actor.

[digital spoke]

Thx u

[floral compass]

The thing with BTs is when used correctly they kind of force you to keep a reasonable design
With state machines you can absolutely go wild and nobody can stop you

[celest python]

@uneven cloud are you affected from layoffs

[sturdy sun]

Searched everywhere cannot find a way to create my own BT Composite Node, it just does not compile at all. Not even a new Empty class. Tried ue4 and ue5, both give me error, just cannot create BT Composite Node in C++?
please any help

did not find Docs, Tutorials or Examples of Custom BT Composite Node anywhere

(I'm trying to Create a simple "Random Selector", instead of it always executing left from right) But not even an empty class compiles
PS: I've added "AI Module" in my public dependencies, but it did change anything

[floral compass]

This works for me
.h

#pragma once

#include "CoreMinimal.h"
#include "BehaviorTree/BTCompositeNode.h"
#include "BTComposite_Test.generated.h"

UCLASS()
class MUGENBEHAVIORTREE_API UBTComposite_Test : public UBTCompositeNode
{
    GENERATED_BODY()
};

What error message are you getting?

[sturdy sun]

#pragma once

#include "CoreMinimal.h"
#include "BehaviorTree/BTCompositeNode.h"
#include "BTComposite_Test.generated.h"

UCLASS()
class ENEMIES_API UBTComposite_Test : public UBTCompositeNode
{
GENERATED_BODY()
};
Same code

2 Errors:

Severity Code Description Project File Line Suppression State Details
Error LNK2001 unresolved external symbol "public: virtual void __cdecl UBTCompositeNode::InitializeMemory(class UBehaviorTreeComponent &,unsigned char *,enum EBTMemoryInit::Type)const " (?InitializeMemory@UBTCompositeNode@@UEBAXAEAVUBehaviorTreeComponent@@PEAEW4Type@EBTMemoryInit@@@Z) Enemies F:\Unreal\Projetos\Enemies\Intermediate\ProjectFiles\BTComposite_Test.gen.cpp.obj 1

Severity Code Description Project File Line Suppression State Details
Error LNK2001 unresolved external symbol "public: virtual void __cdecl UBTCompositeNode::CleanupMemory(class UBehaviorTreeComponent &,unsigned char *,enum EBTMemoryClear::Type)const " (?CleanupMemory@UBTCompositeNode@@UEBAXAEAVUBehaviorTreeComponent@@PEAEW4Type@EBTMemoryClear@@@Z) Enemies F:\Unreal\Projetos\Enemies\Intermediate\ProjectFiles\BTComposite_Test.gen.cpp.obj 1

[sturdy sun]

something about InitializeMemory and CleanupMemory

just cannot compile it

[light void]

Can Sight Radius and Lose Sight Radius be manipulated from Events or something?
I want a "Stealth" stat which act as a multiplier to it. Like if you've got the stealth upgrade, the detection area get smaller.

[harsh storm]

If you look at those functions, are they exported? IE - something like AIMODULE_API in front of them.

[floral compass]

In 5.3 at least they're exported, what version are you using?

Also make sure you really have "AIModule" as a dependency and generated your VS project files

[floral compass]

That sounds weird, because it would affect your AI's sight for everything, not just the player with the high stat.
You probably want to have like a stealth threshold for each AI where you still perceive like you normally would but have an additional check whether the perceived thing's "stealth stat" is above/below a certain threshold

Or have another distance check based on the stealth stat of the perceived thing

[light void]

The issue with that is that it would mean an extra check. Performance wise it is slightly worse

[copper grotto]

If I want to have AI behavior for my player character under certain circumstances, would I hold off calling RunBehaviorTree until I need it to run, or do I run it on event begin play and then set some sort of bool flag to prevent any logic in there from running until the desired time?

[floral compass]

Comparisons and squared distance should be pretty cheap, the profiler will know :p

[floral compass]

Check "RunBehaviorDynamic"

But a bool would do, too

It depends what else is in your tree and whether you need it or not!

[sturdy sun]

5.4
AI Module Added and Empty BT Composite Node Class

If I delete this composite node it compiles again

[copper grotto]

Where would I find that? I don't seem to see it anywhere? I don't need anything else in the behavior tree when the player is in control. This is only for use in certain instances when control is taken from the player.

[floral compass]

That looks correct, not sure about the "AdditionalDependencies" in .uproject, I don't use that. I'm on 5.3 so maybe something changed?

[floral compass]

In that case probably starting the tree at runtime would be better

[copper grotto]

Alright thanks.

[copper grotto]

Any ideas on why my blackboard might be turning up null? I'm trying to set some values on it from the blueprint that's using the AI controller for it. Everything i've checked looks correct (comparing it against another AI setup I had done in another project). But whenever I try to call GetBlackboard, I get this error: PIE: Error: Blueprint Runtime Error: "Accessed None trying to read property CallFunc_GetBlackboard_ReturnValue". Node: Set Value as Vector Graph: CalculateScreenCenter Function: Calculate Screen Center Blueprint: BP_ThirdPersonCharacter

[sturdy sun]

UE5.3 works fine, even without AI Module

UE5.4 though do not compile at all, should we report it?

[floral compass]

Huh. Weird! Do the functions from your error message look different between those versions?

[sturdy sun]

UE5.3 does not get errors at all, it just works, even without AI Modules

[sturdy sun]

UE5.4 do not let you compile even an empty BT Composite Class.
Seems Like two functions are no declared or so...
InitializeMemory
CleanupMemory

[gentle widget]

Hmm

I can't get the state tree AI to work at all. I created two C++ tasks for the state tree (one that acts as an evaluator since I haven't figured out how to make an actual c++ evaluator) to find the player location and another that should just log the player location.

Doesn't seem like the state tree is working at all, I verified to make sure it was attached to my AI character correctly.

[uneven cloud]

No. Been safe so far.

[gentle widget]

Well I figured out my issues with it. I was using a StateTree AI which doesn't seem to work correctly. Even with BP tasks I couldn't make the tree execute. So switching it to a regular state tree schema fixed the not executing bit.

Still can't figure out how to make an evaluator in c++ but using a global task to achieve the same result seems to be working so far.

[copper grotto]

So it seems like I need to call Possess from the AI Controller to get it to take over the player character, but the Possess node says it's only called on the server? I don't see an alternative and my game is not multiplayer so.. what am I supposed to use?

[copper grotto]

Could someone take a look at these bp's and tell me if they look correct as far as making the AI controller possess the player character, and then getting a reference to the controller in the second bp? It seems like it's all debugging right in the first bp, but in the second one I try to get the controller and it comes back as the BP_ThirdPersonController instead of the Ai controller. I've tried using the GetPlayerController node, GetAIController node, and even trying to find the Ai controller by using the GetActorOfClass node since I can see it in the Outliner... but when I do that it doesn't find anything. I'm not sure what I'm missing? https://blueprintue.com/blueprint/36tpbqbs/ , https://blueprintue.com/blueprint/u92e6fzr/

[fathom dome]

So I tried to reparent my AI character fromt he standard BP Character to the standard C++ character

there's only oen issue. They no longer seem to move, they only rotate in place

I checked the visual logger and after a little finagling it seems that it is actually claiming to successfully be moving, it just doesn't happen in game.

any ideas where I should look next?

The nav mesh is there and perfectly fine too by the way

i'm really kind of lost at what could be different between the blueprint and c++ character classes to cause this

or maybe I need to change a reference somewhere?

[dense owl]

Can you show the log

[floral compass]

Indeed, looks different, in 5.3 those functions are not overridden

5.4 BTCompositeNode.h

    virtual void InitializeMemory(UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory, EBTMemoryInit::Type InitType) const override;
    virtual void CleanupMemory(UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory, EBTMemoryClear::Type CleanupType) const override;

5.3 BTNode.h

    /** initialize memory block */
    AIMODULE_API virtual void InitializeMemory(UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory, EBTMemoryInit::Type InitType) const;

    /** cleanup memory block */
    AIMODULE_API virtual void CleanupMemory(UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory, EBTMemoryClear::Type CleanupType) const;

I don't know C++ well enough to say what exactly the problem is, but this seems to be the only difference. Don't know if the overridden functions would need AIMODULE_API as well

[celest python]

Glad to hear that

[random cedar]

Hello guys how can i check it out here when ever the X value falls down or goes up i need to connect the return value of the X from actor location in something that can measure that

[dire fable]

keep tracking of the old x value in a variable and compare to it ?

Hi guys ! How can I block AI movement without blocking character movement component (I want to continue to apply root motion) and without blocking rotation ?

[random cedar]

how to compare it with waht kind of function? ok i have the x value in a variable now

[dense owl]

Near equals + branch

[random cedar]

nicccccceee thanks 😄

[floral compass]

Abort the MoveTo?

[dire fable]

I can abort moveTo with Stop Movement Immediatly

i want to prevent the ai from moving

[floral compass]

No I mean you can abort the AI's MoveTo if you're using behavior trees
Not sure how it works in blueprint

[dire fable]

I'm using BT

I can disable "movement input" from my player with

but I don't know how to do it for AIs

[floral compass]

Using StopMovementImmediately will stop all movement I think, so root motion too maybe? Not sure
And your AIs have no input. So you'll have to abort the MoveTo in your behavior tree instead

[dense owl]

You can also use StopLogic to stop the tree from running entirely but I’m not sure how that would affect the CMC

[dire fable]

I can abort current AI move to and current root motion, its ok. But I want to prevent new ai move to/movement

StopLogic stops the behavior tree. If my AI is in trap, he can no longer move but he can still attack and rotate

[floral compass]

Decorator IsInTrap on the MoveTo node?

[dire fable]

I can try this, but why if I have 15 Behavior trees with 3/4 ai move to tasks in each of them ?

[dense owl]

I want to say you’re trying to apply states to behaviour trees

Which is not ideal

[floral compass]

I mean technically a trap would set your movement speed to 0 instead of disabling the movement request of the AI

[floral compass]

Is that already a case of states in BTs? I find it hard to draw the line sometimes

[dire fable]

maybe it can do the job

[dense owl]

Trapped or not trapped seems stateful?

[floral compass]

True, but so does "Player is in range or not", no?

Unless I'm confusing something

[dire fable]

yes, we don't have "isTrapped" or "isFrozen" or "isStunned" in our game, we have State.MovementBlocked, State.RotationBlocked, State.AttackBlocked, State.AnimationBlocked tags

[floral compass]

Same thing tbh

[dense owl]

Kinda. Point being is if you find yourself having to maneuver around the tree fighting the tool, it’s prly the wrong one

[floral compass]

Guess that's a good approach

[dire fable]

not really, because only 1 decorator "HasNotMovementBlocked" is sufficient

[floral compass]

I find it weird to put the responsibility of "I am trapped" into the AI

Probably belongs elsewhere

[dire fable]

I'll try to set the walk speed to 0

[floral compass]

That's what I would do right now if I had to implement that
Apply a gameplay effect that nulls your current speed for example

[dense owl]

So… GAS? 😀

[dire fable]

Yes, we have GAS. I was going to make an effect that overrides the speed attribute

[floral compass]

Seems the most straightforward solution to me.
I mean, players don't manually have to stop moving when they're trapped right? So why would the AI

[dire fable]

yes that's true, but for the player, I can block move inputs

[floral compass]

Also doesn't sound right to me

😄

[dire fable]

yes it makes more sense

ok it works 👌

[harsh storm]

The problem is those functions aren't exported outside of the module. So things outside of the AIMODULE won't be able to do things with them, IE - override them, or even call them.

You either wait for Epic to fix it, don't update to 5.4, or make source edits and export the methods yourself.

[floral compass]

But they are exported in both 5.3 and 5.4 in BTNode.h
But 5.4 now overrides those functions without export in BTCompositeNode.h, didn't think that would break it

[harsh storm]

Override GetInstanceMemorySize after inheriting from UBTCompositeNode. If it compiles, then that is the problem.

Looks like it broke because they weren't overriding the method in 5.3, but they are in 5.4

It has since been fixed though

Have to wait for the next major release it seems.

So you'll have to patch it yourself.

Unless @crystal hatch can try to get it approved for a 5.4.2 release (if there is going to be a .2 release that is)

[weary bone]

Qestion: i know its kinda stupid but :
How to make AI to react to bool value changes in blackboard?
Also how change Bool value in black board from false to True.
I'm asking because i tried and searched every where - It just doesn't want to work at all.

Just incase Event Call SetIsDead is working fine

[floral compass]

I think "IsNotSet" is the wrong operator. It checks whether a BB key is missing rather than being false or true. You want an equals or not equals instead

[weary bone]

how to do that?

[weary bone]

https://www.youtube.com/watch?v=PcBV-X5R9dE

[weary bone]

Its corrrect
IsNotSet == False
IsSet == True

[floral compass]

Oh, ok!

[lyric flint]

So don't know if anyone can help with this so in the screenshot it's paused

You can see the Current Journey Enum is on ordering

However if I step into you can see it's then set to leaving

and I've found this is why it's skipping over the ordering part

[floral compass]

Why are you doing that via a selector & state enum? Looks like one long sequence to me

[lyric flint]

I found the issue

I had somewhere a move on Journey which was moving it on twice

[undone stream]

Guys why my AI is not flying

When its so far away by the ground its not working

But when it closer it works

[regal drift]

Anyone have any suggestions were how to start getting access to the navmesh and request Async Pathfinding? In C++

Most samples or tutorials use the standard AIController. I want to try and batch numerous Pathfinding requests on Async threads. So i can move plenty of AI agents.

have searched a bit in the following files:
NavigationSystem.h
AbstractNavData.h
AIController.h

Just need some sort nudge me in the right direction. Maybe which functions that would be needed?

[misty wharf]

I don't remember the specifics, but look into the existing navigation functionality that gets paths

there are async functions to calculate paths already in there also

[regal drift]

Thanks for the response

In the AbstractNavData.h i found this FPathFindingResult AAbstractNavData::FindPathAbstract

In NavigationSystem.h there is FPathFindingResult FindPathSync and uint32 FindPathAsync

There were some more when i was searching in the engine files. But these two was those that sounded the most correct.

Guess i should try the NavigationSystem.h and see if i can get it to work.

[misty wharf]

Yeah FindPathAsync would be where I'd start for this

[fathom dome]

@dense owl

you see it doesn't really tell me anything

it thinks everything is going fine

the AI thinks it's moving on the navmesh, it's just not actually doing it.

at least that's my understanding of what i'm reading

[dense owl]

Are you sending the move to request more than once? Also are you clicking on each of the AICon frame and reading the log underneath ?

[fathom dome]

So the log just says "LogPathFollowing (Log) Moving directly to move goal rather than following last path segment" which is fine

it is sending a new attempt to move to every 5 miliseconds

I'm not sure if I'm reading this right but it seems like it's trying to move to, think its doing it, then updates 5 miliseconds later trying to do the same thing since it hasn't actually moved

if it was working it would be a solid bar and stop checking right?

i'm going to change back the parenting and see what its output looks like in compariosn

ignore the first red part, that's just before I turn on the navmesh invoker

I have it on a toggle for testing reasons

so the log is the same, but it definitly shows up differently, you can see it forms a solid bar

the navmesh seems to be pinged more frequently too

could the problem be elsewhere than the AI?

[dense owl]

yeah you shouldn't be doing that

if you keep saying move,move,move, the moveTo task will keep restarting every time and failing to do anything

[fathom dome]

mmm

[dense owl]

it's a latent action you need to allow it time to complete

[fathom dome]

but the other version does that and works

so I think it might be something else, and that's just something I should change

at least I think that's what I'm reading, since the code is not different

only the base class it is a child from

that seems like some bad practice I picked up from a bad tutorial rather than the issue at hand I think

I guess I could try and fix that while I'm looking for the solution though

[dense owl]

what does the first green frame show?

also Luthage would prly encourage you not to use invokers if avoidable, since they are quite expensive perf wise

[fathom dome]

Yeah I am aware of the downsides of nav invokers

but i havn't finalized my decisions on them yet and they're not too hard to swap between

for now they're very useful for testing

[dense owl]

ok. so when the move first happens in that separate frame, what does the log show there

[fathom dome]

I'm not sure what you mean by green frame

[dense owl]

you have a lot of red, followed by 1 green or blue w/e

with a space, and then a solid bar prly due to the attempts on tick

[fathom dome]

oh the yellow one?

on recast navmesh?

[dense owl]

no

on Ai Controller

first frame that is not red

[fathom dome]

I don't see a green one sorry

the first frame that is not red says the same as the others

moving dirrectly to move goal

[dense owl]

that's it? 🤔

[fathom dome]

yep

this is the first frame witht he nav invoker on

and the first green one

er blue

[dense owl]

click on each of the first few frames and see if you find anything like this

if not, look at the last red ones

basically more than just one line

[fathom dome]

they're all blue

the red ones are just because the nav invoker is off so there's no navmesh

once the navinvoker is on the nav mesh errors go away as expected

the log never says anything different between the AI that works with the normal character class and the C++ character class

just their behaviour in the game is different since one can't move

[dense owl]

at least one of those frames should show more than just Moving directly to goal

especially on the bp class which is working as intended from what you described

[fathom dome]

WAIT

I FIGURED IT OUT

oh i'm a dummmy haha

it was the movment componenet

since I was using a custom movement component I forgot that it emptied out the walk speed values

ok now i'll just go and follow your earlier suggestions on ai

thanks so much for helping me out and I did learn a lot about the visual logger 🙂

so I'll do some more research into good AI movement goals, but basically the idea is that they should move all the way to their goal then reassess?

[dense owl]

np

[dense owl]

yeah

ideally you don't want to keep requesting a move when it's still going

if you're using a BT it will do the work for you and wait for it to complete rather than ticking away

otherwise you should prly use the onSuccess/onMoveFinished pins to continue your execution path, if using the regular nodes

[fathom dome]

ok that makes a lot of sense to me

[dense owl]

having said that if your goal location is a moving target, then you probably want to make the multiple requests 😅

[fathom dome]

that makes sense, in this case it's the player character

but I think it would be too bad if it didn't ping too often anyways

It doesn't have to course adjust every 5 mili seconds, once a second is probably enough for a basic AI

[tacit nimbus]

Any ideas as to why Get AIController returns none in this environment query context provider? The Querier Actor definitely has an AI Controller

[misty wharf]

Print the querier to verify it is what you think it is

[gentle widget]

Hey @misty wharf, Do you know how to create a state tree evaluator in C++? I tried following a similar template to the STTask, the code will compile but it won't actually show up as a selectable evaluator in the editor. I'm thinking there's a naming convention that's not inherently obvious.

Also to anyone else that might be able to help, I can't get my state tree to execute more than once. I'm guessing I don't have the correct transition logic setup or my tasks aren't coded properly.

[misty wharf]

You might be inheriting from the wrong base class... iirc there's StateTreeEvaluator and StateTreeEvaluatorCommon or something like this - one of those is wrong

Each state tree has a "schema" which defines which types of evaluators and tasks are valid for it

[gentle widget]

I'm using StateTreeEvaluatorCommonBase

Gotcha, I'll have to dig deeper into it

[misty wharf]

There's the StateTreeComponentSchema (or whatever it was called) which is used when running it from the ST Comp

The other one is StateTreeMassSchema or something like this

you probably want to look at the component one I'm guessing

[gentle widget]

Ahh ok. Yeah let me see what I'm doing, that should at least point me in the right direction on Evaluators hopefully lol

I'm using a global task as a work around in the meantime which has been working fine

lol

My other issue is the state tree is not executing more than once.

[misty wharf]

You may want to use the visual logger or the st debugger to see how it transitions between states

[gentle widget]

Do tick functions execute every frame in a task?

[misty wharf]

It's also possible that if your global task finishes, this can cause the whole ST to effectively freeze