Roblox报错：Attachment必须父级为BasePart，MeshPart为何无效？

我编写了一段LocalScript，通过触发RemoteEvent为角色添加/移除拖尾，但服务器脚本第8行报错“Attachment必须父级为BasePart（Head）”——尽管Head是MeshPart，理论上应该可以正常工作。

本地脚本代码 #

local char = player.Character
local humanoid = char:WaitForChild("Humanoid")
local head = char:WaitForChild("Head")
local HRP = char:WaitForChild("HumanoidRootPart")
local speed = 16 
local maxSpeed = 100
local FlashTrail = game:GetService("ReplicatedStorage"):WaitForChild("FlashTrail")
local DeleteFlashTrail = game:GetService("ReplicatedStorage"):WaitForChild("DeleteFlashTrail")
local function onKeyPress(input)
    if input.KeyCode == Enum.KeyCode.LeftShift then
        if player:GetAttribute("Flash") == true then
            humanoid.WalkSpeed = maxSpeed
            FlashTrail:FireServer(head, HRP)
        end
    end
end

local function onKeyRelease(input)
    if input.KeyCode == Enum.KeyCode.LeftShift then
        if player:GetAttribute("Flash") == true then
            humanoid.WalkSpeed = speed
            DeleteFlashTrail:FireServer(head, HRP)
        end
    end
end

game:GetService("UserInputService").InputBegan:Connect(onKeyPress)
game:GetService("UserInputService").InputEnded:Connect(onKeyRelease)

服务器端脚本代码 #

local DeleteFlashTrail = game:GetService("ReplicatedStorage"):WaitForChild("DeleteFlashTrail")
FlashTrail.OnServerEvent:Connect(function(head, HRP)
    local trail = game.ServerStorage.Trail:Clone()

    trail.Parent = head

    local attachment0 = Instance.new("Attachment",head)

    attachment0.Name = "TrailAttachment0"

    local attachment1 = Instance.new("Attachment",HRP)

    attachment1.Name = "TrailAttachment1"

    trail.Attachment0 = attachment0

    trail.Attachment1 = attachment1
end)

DeleteFlashTrail.OnServerEvent:Connect(function(head, HRP)
    head.TrailAttachment0:Destroy()
    HRP.TrailAttachment1:Destroy()
    head.Trail:Destroy()
end)

问题原因与修复方案 #

核心问题：RemoteEvent回调参数顺序错误 #

Roblox的OnServerEvent回调函数第一个参数固定是触发事件的Player对象，你当前的服务器脚本把head、HRP放在了第一个、第二个参数位置，导致服务器把Player实例当成了head——Player显然不是BasePart，因此触发报错。

优化后的服务器脚本 #

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local ServerStorage = game:GetService("ServerStorage")
local FlashTrail = ReplicatedStorage:WaitForChild("FlashTrail")
local DeleteFlashTrail = ReplicatedStorage:WaitForChild("DeleteFlashTrail")

FlashTrail.OnServerEvent:Connect(function(player, headName, hrpName)
    -- 从服务器端重新获取角色实例，避免客户端传递实例的同步问题
    local char = player.Character
    if not char then return end
    local head = char:FindFirstChild(headName)
    local HRP = char:FindFirstChild(hrpName)
    -- 校验部件合法性
    if not (head and HRP and head:IsA("BasePart") and HRP:IsA("BasePart")) then return end

    local trail = ServerStorage.Trail:Clone()
    trail.Parent = head

    -- 显式设置Parent，不推荐Instance.new的第二个参数语法
    local attachment0 = Instance.new("Attachment")
    attachment0.Name = "TrailAttachment0"
    attachment0.Parent = head

    local attachment1 = Instance.new("Attachment")
    attachment1.Name = "TrailAttachment1"
    attachment1.Parent = HRP

    trail.Attachment0 = attachment0
    trail.Attachment1 = attachment1
end)

DeleteFlashTrail.OnServerEvent:Connect(function(player, headName, hrpName)
    local char = player.Character
    if not char then return end
    local head = char:FindFirstChild(headName)
    local HRP = char:FindFirstChild(hrpName)
    if not (head and HRP) then return end

    -- 用?:避免实例不存在时报错
    head:FindFirstChild("TrailAttachment0")?.Destroy()
    HRP:FindFirstChild("TrailAttachment1")?.Destroy()
    head:FindFirstChild("Trail")?.Destroy()
end)

对应修改的本地脚本 #

local Players = game:GetService("Players")
local player = Players.LocalPlayer
-- 等待角色加载完成，避免空引用
local char = player.Character or player.CharacterAdded:Wait()
local humanoid = char:WaitForChild("Humanoid")
local head = char:WaitForChild("Head")
local HRP = char:WaitForChild("HumanoidRootPart")
local speed = 16 
local maxSpeed = 100
local FlashTrail = game:GetService("ReplicatedStorage"):WaitForChild("FlashTrail")
local DeleteFlashTrail = game:GetService("ReplicatedStorage"):WaitForChild("DeleteFlashTrail")

local function onKeyPress(input)
    if input.KeyCode == Enum.KeyCode.LeftShift then
        if player:GetAttribute("Flash") == true then
            humanoid.WalkSpeed = maxSpeed
            -- 传递部件名称而非实例，更安全
            FlashTrail:FireServer(head.Name, HRP.Name)
        end
    end
end

local function onKeyRelease(input)
    if input.KeyCode == Enum.KeyCode.LeftShift then
        if player:GetAttribute("Flash") == true then
            humanoid.WalkSpeed = speed
            DeleteFlashTrail:FireServer(head.Name, HRP.Name)
        end
    end
end

game:GetService("UserInputService").InputBegan:Connect(onKeyPress)
game:GetService("UserInputService").InputEnded:Connect(onKeyRelease)

额外注意事项 #

1. 本地脚本需等待角色加载完成，避免player.Character为空的情况
2. 服务器端操作实例前必须做存在性校验，防止角色销毁后触发报错
3. 不推荐使用Instance.new(class, parent)语法，显式设置Parent更符合Roblox最佳实践

内容的提问来源于stack exchange，提问作者DumBot