Find (square/retangular) size between two points?

I'm currently creating a script that finds the center location between two points**(parts)** and creates a part that is positioned to the center position, and I'm also trying to make it so that it resizes the part to make it so that it covers both Point A and Point B, but I can't seem to figure out how to find the retangular/square size between both of them to cover them both. Here's my script:

local Point1 = workspace.Point1
local Point2 = workspace.Point2

local MidPoint = Instance.new("Part", workspace)
MidPoint.Name = "MidPoint"
MidPoint.Transparency = 0.5
MidPoint.Anchored = true

MidPoint.Position = (Point1.Position:Lerp(Point2.Position, 0.5)) -- works perfectly fine, part is moved to the center
MidPoint.Size = Vector3.new((Point1.Position + Point2.Position).Magnitude) -- part becomes a thin line instead of a square/rentagle that covers both points. I really don't know how to find the proper size

The size is simply the difference in position between the two parts. Which is to say the offset but in absolute terms calculated like so:

function calculateSize(part1, part2)
	local pos1, pos2 = part1.Position, part2.Position
	local x, y, z = math.abs(pos2.X - pos1.X), math.abs(pos2.Y - pos1.Y), math.abs(pos2.Z - pos1.Z)
	return Vector3.new(x,y,z)
end

If you aren't very familiar with vectors, here's some reading:

Basics In relation to Roblox