How to make part's position relative to character inside a bounding area

[TrebsTakeFlight (altruistfeministbaka)]

I’m making a ping pong game and I’m attempting to use a part to determine where the ball will bounce to but I want the part’s position to depend on where the character of the incoming ball is and without the part leaving the table’s surface.

(ex: character is close to the table, part goes towards the table)

[lumizk (luz)]

You can calculate a fixed position relative to the player character in the direction of the table, then restrict that position to the table area with math.clamp.

That’s how I would do it.

-- LocalScript
local RunService = game:GetService("RunService")
local Players = game:GetService("Players")

local tableSurface = workspace:WaitForChild("TableSurface")
local targetPart = workspace:WaitForChild("TargetPart")

local FORWARD_OFFSET = 4

tableSurface.Anchored = true
targetPart.Anchored = true

local function updateTargetPosition(character)
	if not character or not character:FindFirstChild("HumanoidRootPart") then
		return
	end

	local rootPart = character.HumanoidRootPart

	local desiredWorldPosition = rootPart.Position + (tableSurface.CFrame.LookVector * FORWARD_OFFSET)

	local tableCFrame = tableSurface.CFrame
	local tableSize = tableSurface.Size

	local desiredPosInTableSpace = tableCFrame:PointToObjectSpace(desiredWorldPosition)

	local halfSize = tableSize / 2
	local clampedX = math.clamp(desiredPosInTableSpace.X, -halfSize.X, halfSize.X)
	local clampedZ = math.clamp(desiredPosInTableSpace.Z, -halfSize.Z, halfSize.Z)

	local clampedY = halfSize.Y + (targetPart.Size.Y / 2)

	local finalCFrameInTableSpace = CFrame.new(clampedX, clampedY, clampedZ)
	local finalWorldCFrame = tableCFrame:ToWorldSpace(finalCFrameInTableSpace)

	targetPart.CFrame = finalWorldCFrame
end

RunService.RenderStepped:Connect(function()
	updateTargetPosition(Players.LocalPlayer.Character)
end)

tableSurface and targetPart must be in workspace.