# Procedural Terrain generation not changing material type

I have some code on PTG and I want to variate the materials based off of the generator. For example, above y=100, the material will change to snow.

``````local BASE_HEIGHT 		= 50				-- The main height factor for the terrain.
local CHUNK_SCALE 		= 5 				-- The grid scale for terrain generation. Should be kept relatively low if used in real-time.
local RENDER_DISTANCE 	= 50				-- The length/width of chunks in voxels that should be around the player at all times
local X_SCALE 			= 20				-- How much we should strech the X scale of the generation noise
local Z_SCALE 			= 20				-- How much we should strech the Z scale of the generation noise
local GENERATION_SEED	= math.random()		-- Seed for determining the main height map of the terrain.

local chunks = {}

local function chunkExists(chunkX, chunkZ)
if not chunks[chunkX] then
chunks[chunkX] = {}
end
return chunks[chunkX][chunkZ]
end

local function mountLayer(x, heightY, z, material)
local beginY = -BASE_HEIGHT
local endY = heightY
local cframe = CFrame.new(x * 4 + 2, (beginY + endY) * 4 / 2, z * 4 + 2)
local size = Vector3.new(4, (endY - beginY) * 4, 4)
workspace.Terrain:FillBlock(cframe, size, material)
end

function makeChunk(chunkX, chunkZ)
local rootPosition = Vector3.new(chunkX * CHUNK_SCALE, 0, chunkZ * CHUNK_SCALE)
chunks[chunkX][chunkZ] = true -- Acknowledge the chunk's existance.
for x = 0, CHUNK_SCALE - 1 do
for z = 0, CHUNK_SCALE - 1 do
local cx = (chunkX * CHUNK_SCALE) + x
local cz = (chunkZ * CHUNK_SCALE) + z
local noise = math.noise(GENERATION_SEED, cx / X_SCALE, cz / Z_SCALE)
local cy = noise * BASE_HEIGHT
mountLayer(cx, cy, cz, Enum.Material.Grass)
end
end
end

function checkSurroundings(location)
local chunkX, chunkZ = math.floor(location.X / 4 / CHUNK_SCALE), math.floor(location.Z / 4 / CHUNK_SCALE)
local range = math.max(1, RENDER_DISTANCE / CHUNK_SCALE)
for x = -range, range do
for z = -range, range do
local cx = chunkX + x
local cz = chunkZ + z
if not chunkExists(cx, cz) then
makeChunk(cx, cz)
end
end
end
end

while true do
for _, player in pairs(game.Players:GetPlayers()) do
if player.Character then
local humanoidRootPart = player.Character:FindFirstChild("HumanoidRootPart")
if humanoidRootPart then
checkSurroundings(humanoidRootPart.Position)
end
end
end
wait(.5)
end
``````

The issue is when I call `mountLayer(cx, 100, cz, Enum.Material.Snow)`, everything breaks and I cannot get snow to generate above y = 100.

you dont need the enum number, just the name as a string when using `Terrain:FillBlock`