Roblox Animations Reference

Core Objects

Object	Purpose
`Animation`	Asset reference — holds `AnimationId`
`Animator`	Lives inside Humanoid or AnimationController; loads and drives tracks
`AnimationController`	Replaces Humanoid for non-character rigs
`AnimationTrack`	Returned by `LoadAnimation`; controls playback

Where to Run Animation Code

Scenario	Script Type	Location
Local player character	`LocalScript`	`StarterCharacterScripts`
NPC / server-owned model	`Script`	Inside model or `ServerScriptService`

Never play player character animations from a Script — they will not replicate correctly to the local client.

Loading and Playing Animations

-- LocalScript in StarterCharacterScripts
local character = script.Parent
local animator = character:WaitForChild("Humanoid"):WaitForChild("Animator")

local animation = Instance.new("Animation")
animation.AnimationId = "rbxassetid://1234567890"

local track = animator:LoadAnimation(animation)

track:Play()                      -- default fade-in (0.1s), weight 1, speed 1
track:Play(0.1, 1, 0.5)          -- fadeTime, weight, speed

track:AdjustSpeed(1.5)           -- change speed while playing
track:AdjustWeight(0.5, 0.2)     -- weight 0.5, fade over 0.2s

track:Stop()                      -- default fade-out (0.1s)
track:Stop(0.5)                   -- fade out over 0.5s

AnimationTrack Events

-- Fires after fade-out completes
track.Stopped:Connect(function()
    print("Animation finished")
end)

-- Use :Once for one-shot cleanup
track.Stopped:Once(function()
    cleanup()
end)

-- Fires when a named keyframe marker is reached
-- Marker names are set in the Roblox Animation Editor
track:GetMarkerReachedSignal("FootStep"):Connect(function(paramString)
    playFootstepSound()
end)

Looped vs One-Shot

Property	Looped	One-Shot
`track.Looped`	`true`	`false`
Set in	Animation Editor (loop toggle)	Animation Editor
Override at runtime	`track.Looped = false`	`track.Looped = true`
Stops automatically	No — must call `track:Stop()`	Yes — after one cycle

-- Force a looped animation to play once
track.Looped = false
track:Play()
track.Stopped:Once(function() print("Done") end)

Animation Priority and Blending

Priority controls which tracks win on contested joints. Higher priority overrides lower.

Idle < Movement < Action < Action2 < Action3 < Action4 < Core

idleTrack.Priority   = Enum.AnimationPriority.Idle
runTrack.Priority    = Enum.AnimationPriority.Movement
attackTrack.Priority = Enum.AnimationPriority.Action

idleTrack:Play()
runTrack:Play()     -- overrides idle on shared joints
attackTrack:Play()  -- blends on top for joints it owns

Weight adjusts influence when two tracks share the same priority:

trackA:Play(0, 0.6)  -- weight 0.6
trackB:Play(0, 0.4)  -- weight 0.4 — blended on shared joints

Humanoid vs AnimationController

Humanoid (characters and humanoid NPCs)

local animator = character:FindFirstChildOfClass("Humanoid"):FindFirstChildOfClass("Animator")
local track = animator:LoadAnimation(animation)
track:Play()

AnimationController (props, vehicles, creatures)

local controller = model:FindFirstChildOfClass("AnimationController")
local animator = controller:FindFirstChildOfClass("Animator")
if not animator then
    animator = Instance.new("Animator")
    animator.Parent = controller
end
local track = animator:LoadAnimation(animation)
track:Play()

Replacing Default Character Animations

The Animate LocalScript in the character holds animation references. Modify its AnimationId values on CharacterAdded.

-- LocalScript in StarterCharacterScripts
local animate = script.Parent:WaitForChild("Animate")

local function replaceAnim(slotName, newId)
    local slot = animate:FindFirstChild(slotName)
    if slot then
        local animObj = slot:FindFirstChildOfClass("Animation")
        if animObj then animObj.AnimationId = newId end
    end
end

replaceAnim("idle",  "rbxassetid://111111111")
replaceAnim("run",   "rbxassetid://222222222")
replaceAnim("jump",  "rbxassetid://333333333")
replaceAnim("fall",  "rbxassetid://444444444")
replaceAnim("climb", "rbxassetid://555555555")

Available slots: idle, walk, run, jump, fall, climb, swim, swimidle, toolnone, toolslash, toollunge.

Stop All Playing Animations

local function stopAll(animator, fadeTime)
    for _, track in animator:GetPlayingAnimationTracks() do
        track:Stop(fadeTime or 0.1)
    end
end

Quick Playback Reference

track:Play(fadeTime, weight, speed)
-- fadeTime  default 0.1   — blend-in seconds
-- weight    default 1.0   — joint influence (0–1)
-- speed     default 1.0   — playback rate

track.TimePosition   -- current position in seconds (read/write)
track.Length         -- total duration in seconds
track.IsPlaying      -- bool
track.Looped         -- bool (override allowed at runtime)
track.Priority       -- Enum.AnimationPriority
track.WeightCurrent  -- actual blended weight right now
track.WeightTarget   -- target weight after fade

Upper-Body Only Animations

Priority blending affects all joints an animation touches. To play a wave only on the arms while legs animate from run/idle, the animation itself must be authored to only key upper-body bones (leave lower-body joints unkeyed in the Animation Editor). There is no runtime API to mask joints — the solution is in the animation asset, not the script.

Common Mistakes

Mistake	Fix
Playing character animations in a `Script`	Use `LocalScript` in `StarterCharacterScripts`
`LoadAnimation` called on `Humanoid` (deprecated)	Call on `Animator` instead
Two animations fighting on same joints	Assign different `Priority` values
`Stopped` fires immediately	Animation has zero length or wrong `Looped` setting
`GetMarkerReachedSignal` never fires	Marker name misspelled, or animation not re-uploaded after adding markers
NPC animation not visible to other clients	Play from a `Script` (server), not `LocalScript`
`AnimationController` track won't play	Missing `Animator` child inside `AnimationController`

roblox-animations