Why does my pivoting block sink?

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#1

Why does my pivoting block sink over multiple iterations? I’m a bit lost on the math for this one :frowning: I want it to be able to roll across a flat plane.
BlockPivotSink

local Part: Part = game.Workspace.ROLL -- The demensions are the same; 10x10x10
local cycles: number = 8

for i=1, cycles do
	local Pivot: CFrame = Part.CFrame - Vector3.new(0,Part.Size.Y/2,0) 
	local Offset: CFrame = Pivot:Inverse() * Part.CFrame
	Pivot *= CFrame.Angles(math.rad(90/cycles),0,0) 
	Part.CFrame = Pivot * Offset
	task.wait()
end

UPDATE: Here’s a hacky fix for it, but I’m hoping someone has the real math solution.

local Part: Part = game.Workspace.ROLL -- The demensions are the same; 10x10x10

local cycles: number = 10


for i=1, cycles do
	local originY = Part.CFrame.Y
	local Pivot: CFrame = Part.CFrame - Vector3.new(0,(Part.Size.Y/2),0) 
	local Offset: CFrame = Pivot:Inverse() * Part.CFrame
	Pivot *= CFrame.Angles(math.rad(90/cycles),0,0) 
	
	local newCFrame = Pivot * Offset
	local yDelta = originY - newCFrame.Y -- Hacky way to fix the block sinking otherwise...
	Part.CFrame = newCFrame + Vector3.new(0,yDelta,0)
	task.wait()
end