Generating smooth cube terrain using perlin noise?

This question made me look for my old thing. I eventually found it, though I assure you this ain't really focused on, so imperfections may occur.

    local depthTable = {} -- DO NOT EDIT
    local x,z = 100,100
    local amplitude = 160
    local height = 200 -- DO NOT EDIT
    local minimum = 5
    local sea level = 0 -- 0 = normal
    local smoothness = 30 
    local groundheight = 5
    local heightOffset = 100
    local seed = 0 -- DO NOT EDIT
    local naturalAmp = true -- DO NOT EDIT
    local natAMP = 1 -- DO NOT EDIT
    local plainsBiomeSize = 60
    local built = 0 -- DO NOT EDIT
    local depthNo = 0 -- DO NOT EDIT
    local total = 0 -- DO NOT EDIT
    local depthCurrent = 0 -- DO NOT EDIT

    function developVoxelTerrain()
        seed = math.randomseed(tick())
        local seedA = math.random()*100
        for X = 1,x do
            for Z = 1,z do

                if naturalAmp then
                    natAMP = math.noise(X/(smoothness*plainsBiomeSize),Z/(smoothness*plainsBiomeSize),seedA)


                end


                total = x*z
                local no = (heightOffset + math.floor(math.noise(X/smoothness,Z/smoothness,seedA)*amplitude*natAMP)*4)/4-20 + groundheight
                table.insert(depthTable,table.getn(depthTable)+1,no)
                built = built + 1
            end
            wait()
        end

            for R = 1,x do
                for T = 1,z do

                    depthCurrent = depthCurrent + 1

                    local current = depthTable[depthCurrent]
                    depthNo = depthNo + 1
                    for P = 1, current do
                        local part = Instance.new("Part")
                        part.CFrame = CFrame.new(R*4,(minimum*4)+((P*4)),T*4)
                        part.Size = Vector3.new(4,4,4)
                        part.Color = Color3.fromRGB(168,51,48)
                        part.Anchored = true
                        part.Name = "TestSoil"
                        part.Material = "Slate"
                        part.Parent = workspace

                    end

                end
                wait()
            end
            depthNo = 0
        for X = 1,x do

            for Z = 1,z do
                depthNo = depthNo + 1
                local part = Instance.new("Part")
                part.Size = Vector3.new(4,4,4)
                part.Color = Color3.fromRGB(40,255,20)
                part.Anchored = true
                part.Name = "TestGrass"
                part.Position = Vector3.new(X*4,(minimum*4)+depthTable[depthNo]*4+4,Z*4)
                part.Material = "Grass"
                part.Parent = workspace
                total = x*z
                built = built + 1

            end
            wait()
        end
    end
    developVoxelTerrain()

I have long abandoned fiddling with perlin noise so I can't provide you details and simple methods. Sorry.