JIT
Realistic Roblox Character Physics Script
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@jonatansonderlandbre
local humanoid = script.Parent:WaitForChild("Humanoid") local character = script.Parent local rootPart = character:WaitForChild("HumanoidRootPart") local userInputService = game:GetService("UserInputService") local runService = game:GetService("RunService") local physicsService = game:GetService("PhysicsService") humanoid.BreakJointsOnDeath = false humanoid.RequiresNeck = false -- Variables to track state local isRagdolled = false local jointConstraints = {} local physicsConstraints = {} local originalCollisions = {} local ragdollAttachments = {} local stepConnection = nil -- Active Balancing State local steppingFootName = nil -- "LeftFoot" or "RightFoot" or nil local stepTargetPosition = nil local stepCooldown = 0 -- Timer to prevent rapid steps local stepProgress = 0 -- For smooth step interpolation local lastSteppedFoot = "RightFoot" -- Track last foot for alternating local STEP_COOLDOWN_TIME = 0.25 -- Faster steps local STEP_COMPLETION_DISTANCE = 0.4 -- Closer completion -- Tuning Parameters for Active Balancing local BALANCE_LeanThreshold_FB = 0.4 -- Forward/Backward lean sensitivity local BALANCE_LeanThreshold_LR = 0.35 -- Left/Right lean sensitivity local BALANCE_StepDistanceFactor = 6 -- Step length multiplier local BALANCE_StepForce = 12000 -- Force for stepping local BALANCE_StepResponsiveness = 100 -- Step speed local BALANCE_StanceWidth = 2 -- Width between feet local BALANCE_LiftHeight = 0.4 -- Height of foot lift -- Store original collision settings for _, part in pairs(character:GetDescendants()) do if part:IsA("BasePart") then originalCollisions[part] = { CanCollide = part.CanCollide, CollisionGroupId = part.CollisionGroupId, Massless = part.Massless } part.Massless = false end end -- Function to clear physics constraints local function clearRagdollPhysics() if stepConnection then stepConnection:Disconnect(); stepConnection = nil end for _, constraint in pairs(physicsConstraints) do if constraint.Parent then constraint:Destroy() end end physicsConstraints = {} for _, data in pairs(jointConstraints) do if data.constraint and data.constraint.Parent then data.constraint:Destroy() end if data.a1 and data.a1.Parent then data.a1:Destroy() end if data.a2 and data.a2.Parent then data.a2:Destroy() end end jointConstraints = {} for _, att in pairs(ragdollAttachments) do if att and att.Parent then att:Destroy() end end ragdollAttachments = {} steppingFootName = nil stepTargetPosition = nil stepCooldown = 0 stepProgress = 0 end -- Function to create an attachment local function createConstraintAttachment(parentPart, nameSuffix) local att = Instance.new("Attachment"); att.Name = "RagdollAttachment_" .. (nameSuffix or parentPart.Name); att.Parent = parentPart table.insert(ragdollAttachments, att); return att end -- Estimate Center of Mass local function calculateCenterOfMass() local totalMass = 0; local weightedSum = Vector3.zero local parts = { character:FindFirstChild("UpperTorso"), character:FindFirstChild("LowerTorso"), character:FindFirstChild("Head"), rootPart } for _, part in pairs(parts) do if part and part:IsA("BasePart") and not part.Massless then local mass = part:GetMass(); totalMass = totalMass + mass; weightedSum = weightedSum + part.Position * mass end end return totalMass > 0 and weightedSum / totalMass or rootPart.Position end -- Foot planting logic with ground detection local function updateFootPlanting() local down = Vector3.new(0, -1, 0) local raycastParams = RaycastParams.new(); raycastParams.FilterDescendantsInstances = {character}; raycastParams.FilterType = Enum.RaycastFilterType.Exclude local totalMass = 0; for _, child in pairs(character:GetChildren()) do if child:IsA("BasePart") and not child.Massless then totalMass = totalMass + child:GetMass() end end totalMass = totalMass > 0 and totalMass or 20 local footPlantForceMagnitude = totalMass * workspace.Gravity * 0.8 for _, footName in pairs({"LeftFoot", "RightFoot"}) do local footPart = character:FindFirstChild(footName) if footPart then local forceName = footName .. "_PlantForce" local existingForce = physicsConstraints[forceName] if steppingFootName == footName then if existingForce then existingForce.Enabled = false end continue end local origin = footPart.Position local result = workspace:Raycast(origin, down * 3.5, raycastParams) if result then local groundY = result.Position.Y local currentPos = footPart.Position if currentPos.Y > groundY + 0.1 then footPart.Position = Vector3.new(currentPos.X, groundY + 0.05, currentPos.Z) end if not existingForce then local force = Instance.new("VectorForce"); force.Name = forceName; force.Attachment0 = createConstraintAttachment(footPart, "PlantForceAtt") force.RelativeTo = Enum.ActuatorRelativeTo.World; force.Force = Vector3.new(0, -footPlantForceMagnitude, 0); force.Parent = footPart physicsConstraints[forceName] = force else existingForce.Enabled = true; existingForce.Force = Vector3.new(0, -footPlantForceMagnitude, 0) end else if existingForce then existingForce.Enabled = false end end end end end -- Active balancing with realistic stepping local function updateActiveBalance(dt) stepCooldown = math.max(0, stepCooldown - dt) local leftFoot = character:FindFirstChild("LeftFoot") local rightFoot = character:FindFirstChild("RightFoot") if not leftFoot or not rightFoot or not rootPart then return end local com = calculateCenterOfMass() local leftPos = leftFoot.Position local rightPos = rightFoot.Position local avgFootPos = (leftPos + rightPos) / 2 local groundY = math.min(leftPos.Y, rightPos.Y) local forwardXZ = Vector3.new(rootPart.CFrame.LookVector.X, 0, rootPart.CFrame.LookVector.Z).Unit local rightXZ = Vector3.new(rootPart.CFrame.RightVector.X, 0, rootPart.CFrame.RightVector.Z).Unit local comXZ = Vector3.new(com.X, 0, com.Z) local avgFootXZ = Vector3.new(avgFootPos.X, 0, avgFootPos.Z) local offsetVector = comXZ - avgFootXZ local backwardOffset = -offsetVector:Dot(forwardXZ) local forwardOffset = offsetVector:Dot(forwardXZ) local rightwardOffset = offsetVector:Dot(rightXZ) local leftwardOffset = -offsetVector:Dot(rightXZ) -- Handle current step if steppingFootName then local footPart = character:FindFirstChild(steppingFootName) if footPart and stepTargetPosition then stepProgress = math.min(stepProgress + dt * 4, 1) local distToTarget = (footPart.Position - stepTargetPosition).Magnitude local leanCorrected = math.abs(backwardOffset) < BALANCE_LeanThreshold_FB * 0.25 and math.abs(rightwardOffset) < BALANCE_LeanThreshold_LR * 0.25 if distToTarget < STEP_COMPLETION_DISTANCE or leanCorrected then local constraintName = steppingFootName .. "_BalanceStep" if physicsConstraints[constraintName] then physicsConstraints[constraintName].Enabled = false end lastSteppedFoot = steppingFootName steppingFootName = nil stepTargetPosition = nil stepProgress = 0 local rayResult = workspace:Raycast(footPart.Position, Vector3.new(0, -5, 0), raycastParams) if rayResult then footPart.Position = Vector3.new(footPart.Position.X, rayResult.Position.Y + 0.05, footPart.Position.Z) end else local arcHeight = BALANCE_LiftHeight * math.sin(stepProgress * math.pi) local targetXZ = stepTargetPosition local rayResult = workspace:Raycast(targetXZ, Vector3.new(0, -5, 0), raycastParams) local targetY = rayResult and rayResult.Position.Y or groundY stepTargetPosition = Vector3.new(targetXZ.X, targetY + arcHeight, targetXZ.Z) end else steppingFootName = nil stepTargetPosition = nil stepProgress = 0 end return end if stepCooldown > 0 then return end -- Decide to step local stepUrgency = 0 local stepDirFB = 0 local stepDirLR = 0 if backwardOffset > BALANCE_LeanThreshold_FB then stepDirFB = -1; stepUrgency = stepUrgency + (backwardOffset - BALANCE_LeanThreshold_FB) elseif forwardOffset > BALANCE_LeanThreshold_FB then stepDirFB = 1; stepUrgency = stepUrgency + (forwardOffset - BALANCE_LeanThreshold_FB) end if rightwardOffset > BALANCE_LeanThreshold_LR then stepDirLR = 1; stepUrgency = stepUrgency + (rightwardOffset - BALANCE_LeanThreshold_LR) elseif leftwardOffset > BALANCE_LeanThreshold_LR then stepDirLR = -1; stepUrgency = stepUrgency + (leftwardOffset - BALANCE_LeanThreshold_LR) end if stepUrgency < 0.08 then return end local stepDistFB = math.max(0, math.abs(backwardOffset) - BALANCE_LeanThreshold_FB) * BALANCE_StepDistanceFactor local stepDistLR = math.max(0, math.abs(rightwardOffset) - BALANCE_LeanThreshold_LR) * BALANCE_StepDistanceFactor local footToStep = (lastSteppedFoot == "LeftFoot") and rightFoot or leftFoot steppingFootName = footToStep.Name stepProgress = 0 local rayOrigin = com + forwardXZ * stepDirFB * stepDistFB + rightXZ * stepDirLR * stepDistLR local raycastParams = RaycastParams.new(); raycastParams.FilterDescendantsInstances = {character}; raycastParams.FilterType = Enum.RaycastFilterType.Exclude local rayResult = workspace:Raycast(rayOrigin, Vector3.new(0, -5, 0), raycastParams) local targetY = rayResult and rayResult.Position.Y or groundY local stationaryFoot = (steppingFootName == "LeftFoot") and rightFoot or leftFoot local stanceOffset = rightXZ * ((steppingFootName == "LeftFoot") and -1 or 1) * BALANCE_StanceWidth local baseTargetXZ = Vector3.new(stationaryFoot.Position.X, 0, stationaryFoot.Position.Z) + forwardXZ * stepDirFB * stepDistFB + rightXZ * stepDirLR * stepDistLR + stanceOffset stepTargetPosition = Vector3.new(baseTargetXZ.X, targetY + BALANCE_LiftHeight, baseTargetXZ.Z) local constraintName = steppingFootName .. "_BalanceStep" local alignPos = physicsConstraints[constraintName] or Instance.new("AlignPosition") alignPos.Name = constraintName; alignPos.Mode = Enum.PositionAlignmentMode.OneAttachment alignPos.Attachment0 = createConstraintAttachment(footToStep, "BalanceStepAtt") alignPos.MaxForce = BALANCE_StepForce; alignPos.Responsiveness = BALANCE_StepResponsiveness alignPos.Position = stepTargetPosition; alignPos.Parent = footToStep; alignPos.Enabled = true physicsConstraints[constraintName] = alignPos stepCooldown = STEP_COOLDOWN_TIME local torso = character:FindFirstChild("UpperTorso") if torso then local torqueName = "BalanceTorque" local torque = physicsConstraints[torqueName] or Instance.new("Torque") torque.Name = torqueName; torque.Attachment0 = createConstraintAttachment(torso, "BalanceTorqueAtt") torque.RelativeTo = Enum.ActuatorRelativeTo.World; torque.Parent = torso local leanTorque = Vector3.new(rightwardOffset * 600, 0, backwardOffset * 600) torque.Torque = leanTorque.Magnitude > 2000 and leanTorque * (2000 / leanTorque.Magnitude) or leanTorque physicsConstraints[torqueName] = torque end end -- Ragdoll function local function makeRagdoll() if isRagdolled then return end; isRagdolled = true clearRagdollPhysics() local totalMass = 0; for _, child in pairs(character:GetChildren()) do if child:IsA("BasePart") and not child.Massless then totalMass = totalMass + child:GetMass() end end totalMass = totalMass > 0 and totalMass or 20 for _, joint in pairs(character:GetDescendants()) do if joint:IsA("Motor6D") then local part0 = joint.Part0; local part1 = joint.Part1 if part0 and part1 then local a1 = Instance.new("Attachment"); a1.Name = "RagdollJointAttachment"; a1.Parent = part0; a1.CFrame = joint.C0 local a2 = Instance.new("Attachment"); a2.Name = "RagdollJointAttachment"; a2.Parent = part1; a2.CFrame = joint.C1 local constraint = Instance.new("BallSocketConstraint"); constraint.Parent = part0; constraint.Attachment0 = a1; constraint.Attachment1 = a2 constraint.LimitsEnabled = true; constraint.UpperAngle = 45; constraint.TwistLimitsEnabled = true; constraint.TwistLowerAngle = -30; constraint.TwistUpperAngle = 30 table.insert(jointConstraints, {constraint = constraint, a1 = a1, a2 = a2, part0 = part0, part1 = part1, originalC0 = joint.C0, originalC1 = joint.C1, jointName = joint.Name, jointParent = joint.Parent}) joint:Destroy() end end end for _, part in pairs(character:GetChildren()) do if part:IsA("BasePart") then part.CanCollide = true; part.Massless = false; if part.Name == "HumanoidRootPart" then part.CanCollide = false end end end humanoid:ChangeState(Enum.HumanoidStateType.Physics) local standForce = Instance.new("VectorForce"); standForce.Name = "AntiGravityForce"; standForce.Attachment0 = createConstraintAttachment(rootPart, "AntiGravityAtt") standForce.RelativeTo = Enum.ActuatorRelativeTo.World; standForce.Force = Vector3.new(0, totalMass * workspace.Gravity * 0.98, 0); standForce.Parent = rootPart physicsConstraints[standForce.Name] = standForce stepConnection = runService.Stepped:Connect(function(dt) updateFootPlanting(); updateActiveBalance(dt) end) end -- Reset function local function resetCharacter() if not isRagdolled then return end; isRagdolled = false if stepConnection then stepConnection:Disconnect(); stepConnection = nil end clearRagdollPhysics() for part, data in pairs(originalCollisions) do if part.Parent then part.CanCollide = data.CanCollide; part.Massless = data.Massless end end humanoid:ChangeState(Enum.HumanoidStateType.GettingUp) end -- Event connections humanoid.Died:Connect(function() if not isRagdolled then task.wait(0.05); makeRagdoll() end end) userInputService.InputBegan:Connect(function(input, gameProcessed) if not gameProcessed and input.UserInputType == Enum.UserInputType.Keyboard then if input.KeyCode == Enum.KeyCode.R and humanoid.Health > 0 then if isRagdolled then resetCharacter() else makeRagdoll() end end end end) make this balancing code way more realistic and humanlike, like euphoria, make no errors
Gemini 2.5 Pro

Okay, I will enhance the realism and human-like qualities of the active balancing ragdoll script. This involves refining the center of mass calculation, improving the balance and stepping logic, adjusting joint constraints, and adding more subtle corrective forces.

Key Improvements:

  1. More Accurate CoM: calculateCenterOfMass now includes arms and legs for a better estimate.
  2. Predictive Balancing: updateActiveBalance now predicts the CoM's future position (PREDICTION_TIME) to decide when to step, making it more proactive.
  3. Improved Stepping Logic:
    • Steps are triggered when the predicted CoM goes too far outside the support polygon (line between feet).
    • Step target aims to place the foot to re-center the predicted CoM over the new stance.
    • Step duration and lift height are configurable (STEP_DURATION_MIN/MAX, STEP_LIFT_HEIGHT).
    • Stepping uses VectorForce for smoother, physics-based foot movement towards an arcing target position.
  4. Enhanced Foot Planting:
    • updateFootPlanting now uses AlignOrientation to try and keep planted feet flat on the ground.
    • Includes a horizontal VectorForce to simulate friction and resist sliding based on foot velocity and CoM offset.
    • Downward planting force increases as the foot gets closer to the ground (compression).
  5. Continuous Torso Balancing: applyBalanceTorques runs constantly when ragdolled, applying torque to the UpperTorso (or RootPart as fallback) to counteract lean based on CoM position and velocity (PD controller). Torque is clamped (MAX_BALANCE_TORQUE).
  6. Refined Joint Limits: Basic tuning of BallSocketConstraint limits based on joint type in makeRagdoll. This is still an approximation but better than uniform limits.
  7. Better State Management: Clear separation between makeRagdoll and resetCharacter, ensuring constraints and motors are handled correctly.
  8. Configuration Variables: Many key parameters are now at the top for easier tuning.
  9. Robustness: Added checks for parts existing, uses pcall for GetMass which can sometimes error. Calculates totalMass more reliably.
  10. Code Structure: Logic is broken down into more functions (getSupportPolygon, applyBalanceTorques, etc.).

How to Use:

  1. Place the script RealisticRagdoll.server.lua inside StarterPlayer > StarterCharacterScripts in your Roblox project.
  2. Press 'R' to toggle the ragdoll state while alive. The character will automatically ragdoll upon death.
  3. Adjust the configuration variables at the top of the script to fine-tune the balancing behavior.

This version provides a much more dynamic and reactive balancing system, closer to the desired human-like behavior. Remember that achieving true Euphoria-level physics requires highly complex underlying systems, but this script significantly improves upon the basic approach using Roblox's physics tools.*_

Updated files
v1