Mouse tooltip for showing name of hovered part. (StarterGui LocalScript in Roblox Studio)

README

1. Setup StarterGui
  - PartTooltip (Frame)
    - PartTooltip (LocalScript)
      - Whitelist (ObjectValue that has a Value of the whitelist object or folder [Optional])
    - Text (TextLabel)
    - UICorner [Optional]
  
2. Create an "Offset" (Vector2) attribute for PartTooltip LocalScript.
3. Create a "Distance" (Number) attribute for PartTooltip LocalScript. (This is max distance to show tooltip)

PartTooltip.lua

local RunService = game:GetService("RunService")
local TextService = game:GetService("TextService")

local tooltip = script.Parent
local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
local tooltipSizeOffset = tooltip.AbsoluteSize - tooltip.Text.AbsoluteSize

local function GetWhitelistedMouseTarget()
	local target = mouse.Target
	if not target then return nil end
	
	local whitelist = script.Whitelist.Value
	if whitelist and not target:IsDescendantOf(whitelist) then return nil end
	
	if target then
		local maxDistance = script:GetAttribute("Distance")
		if maxDistance and maxDistance >= 0 then
			local distance = player:DistanceFromCharacter(target.Position)
			if distance > maxDistance then
				target = nil
			end
		end
	end
	
	return target
end

local function GetTooltipPosition()
	local offset = script:GetAttribute("Offset") or Vector2.zero
	return UDim2.new(0, mouse.X + offset.X, 0, mouse.Y + offset.Y)
end

local function GetTooltipSize()
	return UDim2.new(0, tooltip.Text.TextBounds.X + tooltipSizeOffset.X, 0, tooltip.Text.TextBounds.Y + tooltipSizeOffset.Y)
end

RunService.Heartbeat:Connect(function()
	local target = GetWhitelistedMouseTarget()
	tooltip.Visible = target
	if not target then return end
	
	tooltip.Text.Text = target.Name
	tooltip.Position = GetTooltipPosition()
	tooltip.Size = GetTooltipSize()
end)