Help with a moving platform

[hollow dagger]

Hi people can someone help me?

I got a moving platform using physics and i want to make a inertia for it so once i jump i dont get off the platform. I saw on forums that jailbreak train system post and tried to replicate that. It worked very well for tweening parts but bugs out for physics based movers.

I adjusted the code a bit to work better but there still some problems that happens. The code is:

if hitResult then
--checks if the player is jumping, falling down, climbing or in free fall
        if humanoidState[humanoid:GetState()] then
            
            if not lastPlatformCf then
                lastPlatformCf = platform.CFrame
            end
            
            local relCf = platform.CFrame * lastPlatformCf:Inverse()
            lastPlatformCf = platform.CFrame -- update the lastPlatformCf
            rootPart.CFrame = relCf * rootPart.CFrame
        else
            --resets if the localplayer is not jumping
            lastPlatformCf = nil
        end
    else
        --resets if the localplayer is not in the platform
        lastPlatformCf = nil
    end

Roblox handles the contact and the code runs only when player jumps, it works when the platform is in low/normal speed, whoever it bugs out and push the player foward at high speed.

if someone can help me out with this i appreciate.

Here both videos at normal and high speed

[scarlet bear]

Hows it going

Try applying a relative transformation to the players humanoidrootpart based on the platforms motion

it works way better for tweened platforms because their motion is deterministic and frame perfect

physic based movers like bodymover vectoirforce ect have inconsitencies

Use renderstepped over heartbeat or stepped because its synced with the camera and player movement

(local)

I would also avoid lastplatform Cf everyframe because it will cause misalignment if you jump right after stepping on it

or you could set it up like this

`local lastPlatformCf = nil
local runservice = game:GetService("RunService")

RunService.RenderStepped:Connect(function(dt)
local character = game.Players.LocalPlayer.Character
if not character then return end

local rootPart = character:FindFirstChild("HumanoidRootPart")
local humanoid = character:FindFirstChildOfClass("Humanoid")
if not rootPart or not humanoid then return end`

and you can use raycasting to detect platform

[hollow dagger]

Oh ye im already using that, except running it on renderstepped

about the relative transformation

doenst this already does that?

            local relCf = platform.CFrame * lastPlatformCf:Inverse()
            lastPlatformCf = platform.CFrame -- update the lastPlatformCf
            rootPart.CFrame = relCf * rootPart.CFrame

[scarlet bear]

Yes but its the timing and consistency with the inputs

[hollow dagger]

heres the whole function tho mybad for not posting it all

local function syncPlayerWithPlatform()
    local character = localPlayer.Character or localPlayer.CharacterAdded:Wait()
    if not character then return end
    
    local humanoid = character:FindFirstChild('Humanoid')
    if not humanoid then return end
    
    local rootPart = character:FindFirstChild('HumanoidRootPart')
    if not rootPart then return end

    local rayOrigin = rootPart.CFrame.Position
    local hitResult = workspace:Raycast(rayOrigin, rayDirection, rayParams)

    if hitResult then
        --checks if the player is jumping, falling down, climbing or in free fall
        if humanoidState[humanoid:GetState()] then
            
            if not lastPlatformCf then
                lastPlatformCf = platform.CFrame
            end
            
            local relCf = platform.CFrame * lastPlatformCf:Inverse()
            lastPlatformCf = platform.CFrame -- update the lastPlatformCf
            rootPart.CFrame = relCf * rootPart.CFrame
        else
            --resets if the localplayer is not jumping
            lastPlatformCf = nil
        end
    else
        --resets if the localplayer is not in the platform
        lastPlatformCf = nil
    end
end

[fiery violet]

** You are now Level 1! **

[scarlet bear]

what are you using to define platform

hitResult.instance?

[hollow dagger]

no no is the instance im standing on

the raycast params only includes that platform

so no need to check if its the right one

local platform = workspace:WaitForChild('standingPlatform')
local runService = game:GetService("RunService")
local localPlayer = game.Players.LocalPlayer
 
local lastPlatformCf
local filteredInstances = { platform }
local humanoidState = {
    [Enum.HumanoidStateType.Jumping] = true,
    [Enum.HumanoidStateType.FallingDown] = true,
    [Enum.HumanoidStateType.Freefall] = true,
    [Enum.HumanoidStateType.Climbing] = true
}

local rayDirection = Vector3.new(0,-15, 0)
local rayParams = RaycastParams.new()
rayParams.FilterDescendantsInstances = filteredInstances
rayParams.FilterType = Enum.RaycastFilterType.Include

the definitions

[scarlet bear]

thats good

[fiery violet]

** You are now Level 2! **

[hollow dagger]

its all running in the client as well

[scarlet bear]

are you trying to make it run multiplayer?

[hollow dagger]

Yes i have set one is just disabled atm

It send the positions to the server using instance values in the player character, so clients get the info from there and update it as well

[hollow dagger]

So what could i do 😭

i changed to renderstepped too

before it was running with heartbeat. Doenst changed much tho

Is the inputs fine or there something i could change

[hasty sparrow]

bro

why u not just weldconstraint to platform ;-;

wat is this

[hollow dagger]

what bro

weld myself in the platform?

💀

[hasty sparrow]

yes, while touching it keep humanoidrootpart weldconstrainted to the platform and for wasd integrate the positional movement unit vector difference to the part position on the weld constraint every render stepped. ts not rocket science ;-;

that way u will always move relatively to the part without a janky effect

[hollow dagger]

Ill try that didnt came to my mind welding myself on it