Roblox Snow Deformation

-- made by @RobeeSeth

local basepart = script.Parent
local resetpart = workspace:WaitForChild("reset")

local gridsize = 1 -- 1 = 1 stud part, higher means it'd be more optimized, but less precise, since there'd be less parts to step on, I haven't messed with the larger ones since I added foot prints, so it might not work.
local ogheight = 1.2  -- edit this if you want lower or higher snow.
local minheight = 0
local shrinkstep = 0.8 -- this is the tiny foot steps you leave behind.
local neighborshrinkstep = 0.6 -- this is the rest of the snow that you step on.
local cooldowntime = 0.35 -- cooldown before you can step on the same snow part again.
local maxpushheight = ogheight + 0.3 -- so, when you step on snow, the snow around that part will get higher.
local maxpushvary = 0.15

local sizex = basepart.Size.X
local sizez = basepart.Size.Z
local basepos = basepart.Position
local partsx = math.floor(sizex / gridsize)
local partsz = math.floor(sizez / gridsize)

local snowmodel = Instance.new("Model")
snowmodel.Name = "snowgrid"
snowmodel.Parent = workspace

local snowgrid = {}

local function setheight(part, newheight)
	part.Size = Vector3.new(part.Size.X, newheight, part.Size.Z)
	part.Position = Vector3.new(
		part.Position.X,
		basepart.Position.Y + basepart.Size.Y / 2 + newheight / 2,
		part.Position.Z
	)
end

local function shrinkbit(part, amount)
	local oldheight = part.Size.Y
	local newheight = math.max(oldheight - amount, minheight)
	if newheight ~= oldheight then
		setheight(part, newheight)
	end
	return oldheight - newheight
end

local function pushtop(part, amount)
	local newheight = math.min(part.Size.Y + amount, maxpushheight)
	if newheight ~= part.Size.Y then
		setheight(part, newheight)
	end
end

local function pushfullnbs(originx, originz, lostvolume)
	local nearby = {}
	for dx = -1, 1 do
		for dz = -1, 1 do
			if dx ~= 0 or dz ~= 0 then
				local nx, nz = originx + dx, originz + dz
				local neighbor = snowgrid[nx] and snowgrid[nx][nz]
				if neighbor and math.abs(neighbor.part.Size.Y - ogheight) < 0.01 then
					table.insert(nearby, neighbor.part)
				end
			end
		end
	end
	if #nearby > 0 then
		local pushper = lostvolume / #nearby
		for _, p in ipairs(nearby) do
			local randpush = math.random() * maxpushvary
			pushtop(p, pushper + randpush)
		end
	end
end

local function shrinknbs(originx, originz, shrinkamt)
	for dx = -1, 1 do
		for dz = -1, 1 do
			if dx ~= 0 or dz ~= 0 then
				local nx, nz = originx + dx, originz + dz
				local neighbor = snowgrid[nx] and snowgrid[nx][nz]
				if neighbor and tick() - neighbor.lastshrink > cooldowntime then
					local lost = shrinkbit(neighbor.part, shrinkamt)
					neighbor.lastshrink = tick()
					pushfullnbs(nx, nz, lost)
				end
			end
		end
	end
end

local function onstepped(part, x, z)
	return function(hit)
		if not hit:IsA("BasePart") then return end
		local data = snowgrid[x][z]
		if tick() - data.lastshrink < cooldowntime then return end
		local char = hit.Parent
		local isplayer = char and char:FindFirstChild("HumanoidRootPart")
		if isplayer then
			local lost = shrinkbit(part, shrinkstep)
			data.lastshrink = tick()
			shrinknbs(x, z, neighborshrinkstep)
			pushfullnbs(x, z, lost)
		else
			if hit.Anchored then return end
			local lost = shrinkbit(part, neighborshrinkstep)
			data.lastshrink = tick()
			shrinknbs(x, z, neighborshrinkstep)
			pushfullnbs(x, z, lost)
		end
	end
end

for x = 0, partsx - 1 do
	snowgrid[x] = {}
	for z = 0, partsz - 1 do
		local partsize = Vector3.new(gridsize, ogheight, gridsize)
		local partpos = Vector3.new(
			basepos.X - sizex / 2 + x * gridsize + gridsize / 2,
			basepos.Y + basepart.Size.Y / 2 + ogheight / 2,
			basepos.Z - sizez / 2 + z * gridsize + gridsize / 2
		)

		local regioncf = CFrame.new(partpos)
		local regionsize = partsize

		local overlap = OverlapParams.new()
		overlap.FilterType = Enum.RaycastFilterType.Exclude
		overlap.FilterDescendantsInstances = {basepart, snowmodel}
		overlap.CollisionGroup = "Default"

		local blocked = false
		local touching = workspace:GetPartBoundsInBox(regioncf, regionsize, overlap)

		for _, other in ipairs(touching) do
			if other:IsA("BasePart") and other.Anchored and other.Transparency < 1 and other.CanCollide then
				local pos, size = other.Position, other.Size
				if pos and size then
					local min = pos - size / 2
					local max = pos + size / 2
					if partpos.X >= min.X and partpos.X <= max.X and
						partpos.Y >= min.Y and partpos.Y <= max.Y and
						partpos.Z >= min.Z and partpos.Z <= max.Z then
						blocked = true
						break
					end
				end
			end
		end

		if not blocked then
			local part = Instance.new("Part")
			part.Size = partsize
			part.Position = partpos
			part.Anchored = true
			part.TopSurface = Enum.SurfaceType.Studs
			part.BottomSurface = Enum.SurfaceType.Smooth
			part.Color = Color3.fromRGB(255, 255, 255)
			part.Material = Enum.Material.Plastic
			part.CanCollide = false  -- edit this if you want to collide with the snow, wouldn't recommend but go ahead.
			part.Parent = snowmodel
			snowgrid[x][z] = {
				part = part,
				lastshrink = 0
			}
			part.Touched:Connect(onstepped(part, x, z))
		end
	end
end

local function resetall()
	for x = 0, partsx - 1 do
		for z = 0, partsz - 1 do
			local pd = snowgrid[x][z]
			if pd then
				setheight(pd.part, ogheight)
			end
		end
	end
end

local click = resetpart:FindFirstChild("ClickDetector")
if click then
	click.MouseClick:Connect(function()
		resetall()
	end)
end