Placement System using the Hitbox of the entire model instead of a specific part

[Adrianchuk (Not_Adrianchuk)]

Hi, I’m having an issue with my grid placement system in Roblox. The script is using the hitbox of the entire model instead of the specific part named “HitBox” that I want it to use. I’ve tried a lot of fixes (from different sources aswell) but can’t get it to use the correct part . Also not everything is made by me, most of it is from a youtube tutorial but i modified it to fit my needs.

Could anyone help me to get it detect the correct part?

Here are 2 scripts that are causing the problem(its most likely the client placer script that causing the wrong hitbox)

Client Placer (Module script):

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local SelectionBoxTemplate = ReplicatedStorage.SelectionBox
local PlacableObjects = ReplicatedStorage:WaitForChild("PlacableObjects")
local TryPlace = ReplicatedStorage:WaitForChild("TryPlace")
local TryDelete = ReplicatedStorage:WaitForChild("TryDelete")
local UserInputService = game:GetService("UserInputService")
local ContextActionService = game:GetService("ContextActionService")
local RunService = game:GetService("RunService")
local CurrentCamera = game.Workspace.CurrentCamera
local PlacementValidator = require(ReplicatedStorage.PlacementValidator)

local PREVIEW_RENDER = "RenderPreview"
local PLACE_ACTION = "Place"
local ROTATE_ACTION = "Rotate"
local DELETE_ACTION = "Delete"
local SWITCH_ACTION = "Switch"

local function CastMouse()
	local MouseLocation = UserInputService:GetMouseLocation()
	local MouseRay = CurrentCamera:ViewportPointToRay(MouseLocation.X, MouseLocation.Y)
	
	return game.Workspace:Raycast(MouseRay.Origin, MouseRay.Direction * 1000)
end

local function AllowTransparent(object: Model, part: Part)
	if object.Name.find("ConveyorBelt", "ConveyorBelt") then
		if part.Name == "Texture Part" then return 1
		else
			return 0
		end
	end
end

local ClientPlacer = {}
ClientPlacer.__index = ClientPlacer

function ClientPlacer.new(plot: Model)
	local self = setmetatable({
		Plot = plot,
		Preview = nil,
		PreviewIndex = 1,
		Rotation = 0
	}, ClientPlacer)
	
	self:InitiateRenderPreview()
	
	ContextActionService:BindAction(PLACE_ACTION, function(...) self:TryPlaceObject(...) end, false, Enum.UserInputType.MouseButton1)
	ContextActionService:BindAction(ROTATE_ACTION, function(...) self:RotateObject(...) end, false, Enum.KeyCode.R)
	ContextActionService:BindAction(DELETE_ACTION, function(...) self:TryDeleteObject(...) end, false, Enum.KeyCode.X)
	ContextActionService:BindAction(SWITCH_ACTION, function(...) self:SwitchObject(...) end, false, Enum.KeyCode.E, Enum.KeyCode.Q)
	return self
end

function ClientPlacer:InitiateRenderPreview()
	self:PreparePreviewModel(PlacableObjects:GetChildren()[self.PreviewIndex])
	RunService:BindToRenderStep(PREVIEW_RENDER, Enum.RenderPriority.Camera.Value, function(...) self:RenderPreview(...) end)
end

function ClientPlacer:PreparePreviewModel(model: Model)
	if self.Preview then
		self.Preview:Destroy()
	end
	
	self.Preview = model:Clone()
	local SelectionBox = SelectionBoxTemplate:Clone()
	SelectionBox.Adornee = self.Preview
	SelectionBox.Parent = self.Preview
	
	for _, part in self.Preview:GetDescendants() do
		if part:IsA("BasePart") then
			part.CanCollide = false
			part.CanQuery = false
			part.Transparency = 0.5 -- AllowTransparent(model, part)
		end
	end
	
	self.Preview.Parent = game.Workspace
end

local function SnapToGrid(position: Vector3, snap: number)
	local function Snap(value)
		return math.round(value / snap) * snap
	end
	return Vector3.new(Snap(position.X), Snap(position.Y), Snap(position.Z))
end

function ClientPlacer:RenderPreview()
	local Cast = CastMouse()
	if Cast and Cast.Position then
		local Cframe = CFrame.new(SnapToGrid(Cast.Position, 0.5)) * CFrame.Angles(0, self.Rotation, 0)
		self.Preview:PivotTo(Cframe)
		
		local Size = self.Preview:GetExtentsSize()--Vector3.new(self.Preview:FindFirstChild("HitBox").Size.X, self.Preview:FindFirstChild("HitBox").Size.Y, self.Preview:FindFirstChild("HitBox").Size.Z)
		
		self.Preview.SelectionBox.Color3 =
			if PlacementValidator.WithinBounds(self.Plot, Size, Cframe, self.Preview)
			and PlacementValidator.NotIntersectingObjects(self.Plot, Size, Cframe, self.Preview)
			then Color3.new(0.45, 0.65, 1)
			else Color3.new(1, 0.45, 0.45)
	end
end

function ClientPlacer:TryPlaceObject(_, state, _)
	if state ~= Enum.UserInputState.Begin then
		return
	end
	
	local success = TryPlace:InvokeServer(self.Preview.Name, self.Preview:GetPivot())
end

function ClientPlacer:RotateObject(_, state, _)
	if state == Enum.UserInputState.Begin then
		self.Rotation += math.pi / 2
	end
end

function ClientPlacer:TryDeleteObject(_, state, _)
	if state ~= Enum.UserInputState.Begin then
		local Cast = CastMouse()
		if Cast and Cast.Instance then
			local success = TryDelete:InvokeServer(Cast.Instance)
		end
	end
end

function ClientPlacer:SwitchObject(_, state, object)
	if state == Enum.UserInputState.Begin then
		local Objects = PlacableObjects:GetChildren()
		local Direction = if object.KeyCode == Enum.KeyCode.E then 1 else -1
		self.PreviewIndex = (self.PreviewIndex - 1 + Direction) % #Objects + 1
		self:PreparePreviewModel(Objects[self.PreviewIndex])
	end
end

function ClientPlacer:Destroy()
	if self.Preview then
		self.Preview:Destroy()
	end
	RunService:UnbindFromRenderStep(PREVIEW_RENDER)
	
	ContextActionService:UnbindAction(PLACE_ACTION)
	ContextActionService:UnbindAction(ROTATE_ACTION)
	ContextActionService:UnbindAction(DELETE_ACTION)
	ContextActionService:UnbindAction(SWITCH_ACTION)
end


return ClientPlacer

And Placement Validator (Module script):

local PlacementValidator = {}

local AdjustedObjectSize
local Margin = Vector3.new(0.2,0.2,0.2)
local ShrinkFactor = 0.9

function PlacementValidator.WithinBounds(plot: Model, objectSize: Vector3, worldCF: CFrame, object: Model)

	local PlotCF, PlotSize = plot:GetBoundingBox()
	local ObjectCF = PlotCF:ToObjectSpace(worldCF)
	
	AdjustedObjectSize = objectSize - Margin
	
	local CornerPoints = {}
	for _, x in {-1, 1} do
		for _, z in {-1, 1} do
			table.insert(CornerPoints, ObjectCF:PointToWorldSpace(
				Vector3.new(x * AdjustedObjectSize.X / 2, 0, z * AdjustedObjectSize.Z / 2)
			))
		end
	end
	
	for _, corner in CornerPoints do
		if math.abs(corner.X) > PlotSize.X / 2 or math.abs(corner.Z) > PlotSize.Z / 2 then
			return false
		end
	end
	
	return true
end

function PlacementValidator.NotIntersectingObjects(plot: Model, objectSize: Vector3, worldCF: CFrame, object: Model)
	
	local Parameters = OverlapParams.new()
	Parameters:AddToFilter(plot:WaitForChild("Objects"))
	Parameters.FilterType = Enum.RaycastFilterType.Include
	
	local players = game:GetService("Players")
	for _, player in ipairs(players:GetPlayers()) do
		if player.Character then
			Parameters:AddToFilter(player.Character)
		end
	end

	
	local AdjustedObjectSize = objectSize - Margin
	local Parts = game.Workspace:GetPartBoundsInBox(worldCF, AdjustedObjectSize, Parameters)
	return #Parts == 0
end

return PlacementValidator 

Images of the error:

(also it has a wierd bug as shown in the last image)