local terrainRegion = workspace.Terrain:CopyRegion(workspace.Terrain.MaxExtents)
workspace.Terrain:Clear()

task.wait(5)

workspace.Terrain:PasteRegion(terrainRegion, workspace.Terrain.MaxExtents.Min, true)

local Terrain = workspace.Terrain

-- Create a simple terrain region
local initialRegion = Region3.new(Vector3.zero, Vector3.one * 10)
Terrain:FillRegion(initialRegion, 4, Enum.Material.Grass)

-- Copy the region
local copyRegion = Region3int16.new(Vector3int16.new(0, 0, 0), Vector3int16.new(10, 10, 10))
local copiedRegion = Terrain:CopyRegion(copyRegion)

-- Define where to paste the region
local newRegionCorner = Vector3int16.new(5, 0, 0)

-- Paste the region
Terrain:PasteRegion(copiedRegion, newRegionCorner, true)

local REGION_START = Vector3.new(-20, -20, -20)
local REGION_END = Vector3.new(20, 20, 20)

local function printRegion(terrain, region)
	local channelOutput = terrain:ReadVoxelChannels(region, 4, { "SolidOccupancy", "SolidMaterial", "LiquidOccupancy" })
	local size = channelOutput.Size
	for x = 1, size.X do
		for y = 1, size.Y do
			for z = 1, size.Z do
				print(
					("(%2i, %2i, %2i): %.2f %s %.2f"):format(
						x,
						y,
						z,
						channelOutput.SolidOccupancy[x][y][z],
						channelOutput.SolidMaterial[x][y][z].Name,
						channelOutput.LiquidOccupancy[x][y][z]
					)
				)
			end
		end
	end
end

local region = Region3.new(REGION_START, REGION_END)
printRegion(workspace.Terrain, region)

local REGION_START = Vector3.new(-20, -20, -20)
local REGION_END = Vector3.new(20, 20, 20)

local function printRegion(terrain, region)
	local materials, occupancies = terrain:ReadVoxels(region, 4)

	local size = materials.Size -- Same as occupancies.Size

	for x = 1, size.X, 1 do
		for y = 1, size.Y, 1 do
			for z = 1, size.Z, 1 do
				print(("(%2i, %2i, %2i): %.2f %s"):format(x, y, z, occupancies[x][y][z], materials[x][y][z].Name))
			end
		end
	end
end

local region = Region3.new(REGION_START, REGION_END)

printRegion(workspace.Terrain, region)

local terrain = workspace.Terrain
local region = Region3.new(Vector3.new(-20, -20, -20), Vector3.new(20, 20, 20))
local resolution = 4
local materialToReplace = Enum.Material.Grass
local replacementMaterial = Enum.Material.Asphalt

terrain:ReplaceMaterial(region, resolution, materialToReplace, replacementMaterial)

local region = Region3.new(Vector3.new(0, 0, 0), Vector3.new(64, 32, 64))

local RESOLUTION = 4
local OCC_EPSILON = 1 / 256

local function generateRandomTerrainInRegion(regionInput)
	local region = regionInput:ExpandToGrid(4)
	local size = region.Size / 4
	local solidMaterials = {}
	local solidOccupancies = {}
	local waterOcc = {}

	for x = 1, size.X do
		table.insert(solidMaterials, {})
		table.insert(solidOccupancies, {})
		table.insert(waterOcc, {})

		for y = 1, size.Y do
			table.insert(solidMaterials[x], {})
			table.insert(solidOccupancies[x], {})
			table.insert(waterOcc[x], {})

			for z = 1, size.Z do
				local mat = if math.random() < 0.5 then Enum.Material.Air else Enum.Material.Sand
				local occ = 0
				local water = math.random()
				if mat == Enum.Material.Sand then
					occ = math.random() / 2 + 0.5
					if occ > 1 - OCC_EPSILON then
						water = 0 -- Solids cannot contain water
					end
				else
					occ = 0
				end
				table.insert(solidMaterials[x][y], mat)
				table.insert(solidOccupancies[x][y], occ)
				table.insert(waterOcc[x][y], water)
			end
		end
	end
	return { SolidMaterial = solidMaterials, SolidOccupancy = solidOccupancies, LiquidOccupancy = waterOcc }
end

local regionContent = generateRandomTerrainInRegion(region)
workspace.Terrain:WriteVoxelChannels(region, 4, regionContent)

local terrain = workspace.Terrain
local resolution = 4
local region = Region3.new(Vector3.new(0, 0, 0), Vector3.new(16, 28, 20)):ExpandToGrid(resolution)
local materials = {
	{
		{
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
		},
		{ Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock },
		{ Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock },
		{ Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand },
		{ Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand },
		{ Enum.Material.Mud, Enum.Material.Mud, Enum.Material.Mud, Enum.Material.Mud, Enum.Material.Mud },
		{ Enum.Material.Air, Enum.Material.Air, Enum.Material.Air, Enum.Material.Air, Enum.Material.Air },
	},
	{
		{
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
		},
		{ Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock },
		{ Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock },
		{ Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand },
		{ Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand },
		{ Enum.Material.Mud, Enum.Material.Snow, Enum.Material.Snow, Enum.Material.Snow, Enum.Material.Mud },
		{ Enum.Material.Air, Enum.Material.Snow, Enum.Material.Snow, Enum.Material.Snow, Enum.Material.Air },
	},
	{
		{
			Enum.Material.CrackedLava,
			Enum.Material.Sand,
			Enum.Material.Sand,
			Enum.Material.Sand,
			Enum.Material.CrackedLava,
		},
		{ Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock },
		{ Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock },
		{ Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand },
		{ Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand },
		{ Enum.Material.Mud, Enum.Material.Snow, Enum.Material.Snow, Enum.Material.Snow, Enum.Material.Mud },
		{ Enum.Material.Air, Enum.Material.Snow, Enum.Material.Snow, Enum.Material.Snow, Enum.Material.Air },
	},
	{
		{
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
			Enum.Material.CrackedLava,
		},
		{ Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock },
		{ Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock, Enum.Material.Rock },
		{ Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand },
		{ Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand, Enum.Material.Sand },
		{ Enum.Material.Mud, Enum.Material.Mud, Enum.Material.Mud, Enum.Material.Mud, Enum.Material.Mud },
		{ Enum.Material.Air, Enum.Material.Air, Enum.Material.Air, Enum.Material.Air, Enum.Material.Air },
	},
}
local occupancies = {
	{
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 0.5, 0.5, 0.5, 0.5, 0.5 },
		{ 0, 0, 0, 0, 0 },
	},
	{
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 0.5, 1, 1, 1, 0.5 },
		{ 0, 1, 1, 1, 0 },
	},
	{
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 0.5, 1, 1, 1, 0.5 },
		{ 0, 1, 1, 1, 0 },
	},
	{
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 1, 1, 1, 1, 1 },
		{ 0.5, 0.5, 0.5, 0.5, 0.5 },
		{ 0, 0, 0, 0, 0 },
	},
}

terrain:WriteVoxels(region, resolution, materials, occupancies)