Method for hitbox detection

[pastel temple]

What are some light but effective ways to make hitboxes? Right now my bright idea is to just simulate a bounding box with math, but im just curious what other methods people use

[ebon sparrow]

** You are now Level 3! **

[rain ridge]

Hitbox:destroy()

[lilac orchid]

People tend to use raycasts as they're the most reliable

This library (which is the successor to Raycast hitboxes) may help: https://devforum.roblox.com/t/shapecasthitbox-for-all-your-melee-needs-v025/3624241

[pastel temple]

a problem ive run into with using raycast is that it only will be able to detect one player, not sure if there are ways around this so please lmk if there are

[snow hollow]

use spatial queries like workspace:getpartsinbox/sphere/etc

i'd suggest avoid using getpartsinpart to save creating an instance, unless the hitbox should last for several frames in which case you can also use .touch

or just use a spatial query every frame

up to you 🤷

[pastel temple]

what im currently doing is filtering through a list of parts tagged damagable, and checking if relevant parts are inside the box, im not sure if this is more or less efficient, i kinda feel like its less

function Punchingv1:Create_boundB(HumanoidRootPart: BasePart)
    local boundBoxSize = Vector3.new(6,6,5)
    local localboundBoxOffset = HumanoidRootPart.CFrame * CFrame.new(0,0,((boundBoxSize.Z/2)+0.7)*-1)
    -- Visualization (for debugging)
    local visual = Instance.new("Part")
    visual.Name = "PunchDebugBox"
    visual.Size = boundBoxSize
    visual.CFrame = localboundBoxOffset
    visual.Anchored = true
    visual.CanCollide = false
    visual.Transparency = 0.5
    visual.Color = Color3.fromRGB(255, 0, 0)
    visual.Material = Enum.Material.ForceField
    visual.Parent = workspace
    game.Debris:AddItem(visual, 0.2)
    return localboundBoxOffset, boundBoxSize
end
local boundB,BoundBSize = self:Create_boundB(hrp)
    local charHit = {}
    local damageables = collectionService:GetTagged("Damageable")
    for _, model: Model in pairs(damageables) do if model == char then continue end
        for _, part:BasePart in pairs(model:GetChildren()) do
            if part:IsA("BasePart") and damagablesParts[part.Name] then
                local partRelative = boundB:ToObjectSpace(part.CFrame)
                if math.abs(partRelative.X) <= BoundBSize.X and math.abs(partRelative.Y) <= BoundBSize.Y and math.abs(partRelative.Z) <= BoundBSize.Z then
                    table.insert(charHit,model)
                    break
                else
                    continue
                end
            end
        end
    end

[snow hollow]

that's absolutely, utterly insane.

[pastel temple]

😭

[snow hollow]

very bad and you should feel bad

it may seem like i just say things for the sake of saying things, but believe or not, i don't just say things for the sake of saying them, i'm actually trying to meaningfully help you

[pastel temple]

...

[pastel temple]

ok so it was insane and i do feel bad

[serene pebble]

I started an M1 system today and I use a spatial query every frame like pyro said

Works well I suggest that

[real zephyr]

Wym every frame

[serene pebble]

im making an M1 system, every frame of the punch animation i need it to deal damage if a player is inside the hurtbox

so i use a spatial query to add players into a list to do damage to them

[real zephyr]

why not use a single frame for ur hit detection?

[serene pebble]

when moving around if you only use a single frame it might be a bit hard to hit

i use a heart beat connection and a spatial query so say i move around alot it spawns hurtbox parts and stores any players it touches in the list once

then deals the damage

[serene pebble]

its more dynamic and handles movement better

[snow hollow]

some attacks last for multiple frames like a wide sword swing will likely have multiple frames where it should be slashing for aoe radius, and it takes a few frames for the full swing to complete, so you'll need to do a query for every frame it should be damaging

or .touched

[real zephyr]

yeah but that can take a lot of server performance

wouldnt it be better to do a stud buffer instead?

[real zephyr]

Thats true but u can also compensate with a stud buffer

i also want to know the best method so im very open to your ideas

[snow hollow]

i don't think you know enough about programming to be making any statements about performance

most people don't

[snow hollow]

what is stud buffer

[real zephyr]

Increasing hitbox range by a few studs than the weapon visually shows

[snow hollow]

that's not much of a compensation, it's just making the hitbox bigger

[real zephyr]

Rank in this server doesn't mean everything. It's common sense though that an active frame check will be more expensive than a single frame check.

[snow hollow]

you can do some compensation with 2 hitboxes like that but it's complicated as to how you would actually use it

[real zephyr]

Yes making it bigger will allow more leniency with its hits

Deepwoken does this

[snow hollow]

i doubt deepwoken does this

it might do the compensator but it probably doesn't just broadly make the hitbox bigger

it's complicated why you might want to use 2 i'm not going to go into it right now

but it's not as simple as just a bigger hitbox

haven't played deepwoken so i can't say for certain but if they've done their homework they probably have a prediction system with rollback

compensator helps make this more accurate, less prediction errors. but again can't say for certain, just as much as you cannot

we don't have access to deepwoken source code.

[real zephyr]

They actually do if u go into the game u can see the hitbox is extended

[snow hollow]

i refuse to pay for it

[real zephyr]

No we don't but I had a friend who somehow got a copy of the game

[snow hollow]

they didn't "somehow" get a copy, they probably stole it with a decompiler

[real zephyr]

I can assure u it's extended

[real zephyr]

That doesn't steal server code unless I'm wrong

[snow hollow]

correct, only client and shared code no server code

pretty obvious tell how they got it if theres no server code

if they do have server code then 🤷 they might've attempted to reverse engineer it based on client code

still huge job

why bother when you can just make your own

[real zephyr]

They got the server code as fir how I don't know but they told me it's a server side hitbox

[real zephyr]

Your guess is good as mine

[snow hollow]

so they do it the tsb way then

just completely ignore prediction and do everything on the server, input lag be damned

[real zephyr]

It works out for them it seems

[snow hollow]

clearly

[real zephyr]

I would like some advice on prediction

Since I use server side hitboxes is there any benefit to me using cached positions in my checks

[snow hollow]

the full prediction pattern is very difficult to do

i'd suggest waiting for roblox to release their auroraservice instead of trying to make one yourself

[real zephyr]

I guess I should follow deepwokens footsteps then huh? 😭

[snow hollow]

for now

[real zephyr]

What do you do personally?

I mean you clearly have a lot of experience

[snow hollow]

i'll be adding the full prediction pattern to my framework

coz i don't have the luxury of 50 ping on 99% of roblox games

[real zephyr]

What type of predictions will you be using?

Mind spilling the secrets 👀

[snow hollow]

wat

there's only one kind

there are degrees of how much of the pattern you do tho

[real zephyr]

I'm confusing it with lag compensation I think

Networking is my weakest point

[snow hollow]

lag compensation and prediction go hand in hand but they are different concepts

lag compensation is usually called rollback netcode, prediction is where clients predict what the server is going to do before the server responds, sometimes this prediction is incorrect aka misprediction so you get jitter and other visual errors like that

like your character can teleport if big misprediction

[real zephyr]

I see ty for clarifying it

[snow hollow]

if you've played any source engine games like csgo, gmod or tf2 you'll have experienced the full prediction pattern

[real zephyr]

I tried implementing predictikdn with my combat framework

Didn't go very well

[snow hollow]

yea you need s3~s4 tier skills to make it

very difficult

[real zephyr]

Yes, where they teleport you back due to a ping spike

[snow hollow]

yep

packet loss, aka lost inputs will cause misprediction

[real zephyr]

Yes

[snow hollow]

or if your code is wrong it will mispredict as well

[real zephyr]

I assume that's where the usefulness of caching positions comes in for movement predictions

[snow hollow]

but under normal circumstances with minimal packet loss no one will notice

it's not just a cache ;o

much more involved than that

[real zephyr]

Yes ik what u mean

I considered doing predictions for my dashes but I realized it would take a lot more math than I thought

[snow hollow]

anyway i got things to do

[real zephyr]

Yeah man thank you for your time

[serene pebble]

alot of games inflate hitboxes to make it feel more responsive, take overwatch for example

personally though say im punching i would want hurtboxes to spawn that catch the player inside

you may see a game like brawlhalla do this and i think its alot better for games with alot of movement

[pastel temple]

So my current takeaway is to use spacial queries and look into rollback for hitboxes or prediction systems to compensate for ping, that sound about right?

[serene pebble]

roll back requires from my knowledge you to store every players position look vector rotation then states like blocked dodged stunned attack
then to calculate on the server depending on their ms if they should have hit or not

basically dont bother with rollback until your S3-4 or roblox adds something to make it easier

theres probably an easier checklist to make sure your combat feels good

[pastel temple]

ive made a fsm system for every player int eh game already, so im able to easily fetch and store things like states, im guessing the only thing i would need is to store positions and vectors to sanity check whether the other player should have been hit right?

im not sure on optimization and preformance, i just want to see if im understanding how they work

[serene pebble]

im honestly not the most educated on the topic but i think alot of the complexity will come from juggeling things like players ping
how do you determine how far back to go
would depend on how high their latency is i imagine but easier said then done

if you want to give it a shot ofc

then the actual rollback

i think making it look and feel nice is also quite the challange

[real zephyr]

Are there any popular games that use rollback?

Is that a method that only client side hitboxes benefit from or also server side?

[serene pebble]

pyro listed a few but ill add Rainbow six siege as i use to play it alot

if youve ever played high ping and had a hit rejection thats why

oh apparently also OW call of duty and valorant

seems like the industry standard tbh

[real zephyr]

i see, is imore for a system for shooter games, or does melee combat also benefit from this? Also what are your thoughts about the benefits for server vs client?

[serene pebble]

Street Fighter 6, Guilty Gear Strive, Skullgirls, Mortal Kombat 1 also use netcode rollback

[serene pebble]

i would always recommend the server as the one with authority

idk if there is any benefits for doing it client side

potentially responsiveness but it doesnt weight well against the cons

[real zephyr]

Sorry i didnt clarify, i mean for using a rollback system

[serene pebble]

the only type of rollback i know uses both

client predicts
it plays say the punch

then on the server it calculates if that punch should have landed

idk of any client specific rollback systems

[real zephyr]

if the server were to initiate the animation through server side validation, would it still benefit from a rollback?

in other words, if the client didnt use any prediction

[serene pebble]

if it didnt use any prediction imagine it like this

you have high ping and you shoot or hit someone

it wouldnt play any animation to begin with as it wont predict if you did or didnt hit them

then the server would calculate what should have happend rollback if need be and apply the hit

so it would look a bit off especially at higher pings

imagine shooting someone then say 0.3 seconds later you see the shot hear the shot and get the kill

i guess vise versa would be if it predicts against what you experienced you may feel cheated out
you saw your shot landed but the server said it didnt

[real zephyr]

I get that but in a timing sensitive system, its difficult to replicate this either way

i can see how this benefits input _> instant attack

[serene pebble]

ah like stringing a combo

yeah that would be very difficult to implement in a tight frame combo

[real zephyr]

with windups

not an instant attack

[serene pebble]

yeah i get what your saying
if street fighter and mortal kombat can use client side prediction and rollback then im sure its somehow possible

[real zephyr]

street fighter attacks are usually instant/ almost instant

also we have to look at the perspective of all players not just the attacker

if the attacker uses client side prediction, the server will recieve the attack while the client's animation is already somewhat progressed

[serene pebble]

it uses charged moves and i think if anything would be a real challange it would be combos
especially mortal kombat where you can frame skip i think its caleld

[serene pebble]

yes which means the worst outcome is it plays but the player doesnt actually get the hit they saw

but thats more fair than the alternative

[real zephyr]

no, the player that got hit will be facing a delayed hitbox, making it difficult to time/parry according to the animation

[ebon sparrow]

** You are now Level 10! **

[real zephyr]

thats why client prediction for these systems is so rare

[serene pebble]

i mean if one of the biggest fighting games of all time is using prediction in their rollback they must have been able to implement it pretty well

[real zephyr]

im not saying prediction is useless for rollback, but it's pretty difficult to implement in this kind of scenario

especially with roblox's engine

perhaps if there methods to prevent replication from some client animations it would be infinitly more possible

[serene pebble]

well if pyro fire thinks roblox will add some service to make it easier maybe in due time itll be possible for your average developer

[real zephyr]

Hey, i was wondering if i could get some advice on this: My combat framework sends requests to the server to attack where the server validates it with a hitbox. It doesnt use prediction and is a melee system. Should i use a rollback system for it?

[serene pebble]

honestly

if your new to it and just want a working game i think theres more pressing matters that can make your combat feel better easier
lower hanging fruit

if you want to specifically for the fun or experience or have made combat games before and want a step above go for it

[real zephyr]

I currently have one implemented, so I was wonderign if its worth keeping. Do you have any advice for making it feel better in general?

I make the hitbox slightly bigger than visuals so its more consistent too

Im also considered about the scalibility for my polling:

RunService.Heartbeat:Connect(function()
    for character, rollCharacter in pairs(self.HRPCache) do
        rollCharacter:Record()
    end
end)

this polls the positions of the roots

[serene pebble]

not really honestly
a generous hitbox can help
well sycned with the animation

[serene pebble]

you want at a certain stage for it to remove old history

so 500 ms ago is quite unrealistically needed as idk anyone who constantly has to play on 500ms

i think the heavy top end that should be accounted for is 300

so you need say 350ms worth of history saved then after that remove it

or your table will grow and grow

you could try storing only the root

• cframe
• velocity
• maybe rotation or a look vector

instead of the entire character

also you dont need to store every frame

i would try find a nice balance where its accurate but your not oversaving data whatyou dont need to

[real zephyr]

I do around 250 ms of history

[real zephyr]

Do you mean not really to keeping the rollback system or advice for improving a hitbox?