core: broken

src/ReplicatedStorage/Shared/ChunkManager/BlockManager.lua

@@ -23,9 +23,6 @@ end
 local warnedBlockIds = {}
 
 function BlockManager:GetBlock(blockId: number, attr: {[typeof("")]: any}?)
-	
-	task.synchronize()
-	
 	if not BlockManager.BlockIdMappings[blockId] then
 		if not warnedBlockIds[blockId] then
 			warnedBlockIds[blockId] = true
@@ -59,8 +56,6 @@ function BlockManager:GetBlockRotated(blockId: number, face: Enum.NormalId, attr
 	local block = BlockManager:GetBlock(blockId, attr)
 	local rot = CFrame.new()
 
-	task.synchronize()
-
 	if face == Enum.NormalId.Front then
 		rot = CFrame.Angles(0, 0, 0) -- no rot
 	elseif face == Enum.NormalId.Back then

src/ReplicatedStorage/Shared/ChunkManager/Chunk.lua

@@ -75,7 +75,6 @@ function Chunk.from(x,y,z,data)
 end
 
 function Chunk:DoesNeighboringBlockExist(rx, ry, rz, gx, gy, gz, offsetX, offsetY, offsetZ)
-	task.desynchronize()
 	-- Calculate the local position of the neighboring block
 	local neighborRX, neighborRY, neighborRZ = rx + offsetX, ry + offsetY, rz + offsetZ
 	local neighborGX, neighborGY, neighborGZ = gx, gy, gz
@@ -120,7 +119,6 @@ function Chunk:DoesNeighboringBlockExist(rx, ry, rz, gx, gy, gz, offsetX, offset
 end
 
 function Chunk:IsBlockRenderable(rx, ry, rz)
-	task.desynchronize()
 	local gx, gy, gz = self.pos.X, self.pos.Y, self.pos.Z
 	-- Check all six neighboring blocks
 	local d = not (
@@ -144,7 +142,6 @@ function Chunk:PropogateChanges(x: number,y: number,z: number,d:BlockData)
 end
 
 function Chunk:GetBlockAt(x,y,z)
-	task.desynchronize()
 	if not self.data[keyFromCoords(x, y, z)] then
 		return nil
 	end
@@ -176,7 +173,6 @@ end
 
 function Chunk:Unload()
 	
-	task.synchronize()
 	self.loaded = false
 	
 	-- SLOWCLEAR
@@ -194,11 +190,9 @@ function Chunk:Unload()
 			end
 		end
 		
-		task.synchronize()
 		self.instance.Parent = nil
 		self.instance:Destroy()
 		self.unloadChunkHook()
-		task.desynchronize()
 	end)
 end
 

src/ReplicatedStorage/Shared/ChunkManager/ChunkBuilder.lua

@@ -43,8 +43,6 @@ local function Swait(l)
 end
 
 local function propogateNeighboringBlockChanges(cx, cy, cz, x, y, z)
-	--warn("propogateNeighboringBlockChanges",cx,cy,cz,x,y,z)
-	-- updates block in another chunk
 	local c = Chunk.AllChunks[`{cx},{cy},{cz}`]
 	if not c then return end
 
@@ -53,18 +51,14 @@ local function propogateNeighboringBlockChanges(cx, cy, cz, x, y, z)
 
 	if c:IsBlockRenderable(x, y, z) then
 		if c.instance:FindFirstChild(`{x},{y},{z}`) then return end
-		task.synchronize()
 		local block = BlockManager:GetBlockRotated(d.id, util.RotationStringToNormalId(d.state["r"] or "f"), d.state)
 		block.Name = `{x},{y},{z}`
 		block:PivotTo(util.ChunkPosToCFrame(c.pos, Vector3.new(x, y, z)))
 		block.Parent = c.instance
-		task.desynchronize()
 	else
 		local existing = c.instance:FindFirstChild(`{x},{y},{z}`)
 		if existing then
-			task.synchronize()
 			existing:Destroy()
-			task.desynchronize()
 		end
 	end
 end
@@ -80,33 +74,27 @@ function ChunkBuilder:BuildChunk(c: typeof(Chunk.new(0,0,0)),parent: Instance?)
 
 	local finished = false
 
-
 	local ch = Instance.new("Folder")
 	ch.Parent = parent
 	ch.Name = `{c.pos.X},{c.pos.Y},{c.pos.Z}`
 
 	local conn = c.UpdateBlockBindableL.Event:Connect(function(x: number, y: number, z: number, d: BlockData)
-		task.desynchronize()
 		if finished == false then
 			newcache[`{x},{y},{z}`] = d
 			return
 		end
-		task.synchronize()
 		for _, o in pairs(NEIGHBOR_OFFSETS) do
-			--warn("propogate",o[1],o[2],o[3])
-			-- Adjust for chunk boundaries
 			local b = {x = x + o[1], y = y + o[2], z = z + o[3]}
-			local ch = {x = c.pos.X, y = c.pos.Y, z = c.pos.Z}
+			local chPos = {x = c.pos.X, y = c.pos.Y, z = c.pos.Z}
 
-			if b.x < 1 then ch.x = c.pos.X - 1 b.x = 8 end
-			if b.x > 8 then ch.x = c.pos.X + 1 b.x = 1 end
-			if b.y < 1 then ch.y = c.pos.Y - 1 b.y = 8 end
-			if b.y > 8 then ch.y = c.pos.Y + 1 b.y = 1 end
-			if b.z < 1 then ch.z = c.pos.Z - 1 b.z = 8 end
-			if b.z > 8 then ch.z = c.pos.Z + 1 b.z = 1 end
+			if b.x < 1 then chPos.x = c.pos.X - 1 b.x = 8 end
+			if b.x > 8 then chPos.x = c.pos.X + 1 b.x = 1 end
+			if b.y < 1 then chPos.y = c.pos.Y - 1 b.y = 8 end
+			if b.y > 8 then chPos.y = c.pos.Y + 1 b.y = 1 end
+			if b.z < 1 then chPos.z = c.pos.Z - 1 b.z = 8 end
+			if b.z > 8 then chPos.z = c.pos.Z + 1 b.z = 1 end
 
-			propogateNeighboringBlockChanges(ch.x, ch.y, ch.z, b.x, b.y, b.z)
-			--BlockManager:GetBlock(ch.x)
+			propogateNeighboringBlockChanges(chPos.x, chPos.y, chPos.z, b.x, b.y, b.z)
 		end
 
 		local blockName = `{x},{y},{z}`
@@ -116,12 +104,10 @@ function ChunkBuilder:BuildChunk(c: typeof(Chunk.new(0,0,0)),parent: Instance?)
 				c.delayedRemoval[blockName] = nil
 				if existing then
 					task.defer(function()
-						task.synchronize()
 						RunService.RenderStepped:Wait()
 						if existing.Parent then
 							existing:Destroy()
 						end
-						task.desynchronize()
 					end)
 				elseif DEBUG_GHOST then
 					print("[CHUNKBUILDER][GHOST] Delayed remove missing instance", c.pos, blockName)
@@ -129,9 +115,7 @@ function ChunkBuilder:BuildChunk(c: typeof(Chunk.new(0,0,0)),parent: Instance?)
 				return
 			end
 			if existing then
-				task.synchronize()
 				existing:Destroy()
-				task.desynchronize()
 			elseif DEBUG_GHOST then
 				print("[CHUNKBUILDER][GHOST] Remove missing instance", c.pos, blockName)
 			end
@@ -139,26 +123,20 @@ function ChunkBuilder:BuildChunk(c: typeof(Chunk.new(0,0,0)),parent: Instance?)
 		end
 		if not c:IsBlockRenderable(x, y, z) then
 			if existing then
-				task.synchronize()
 				existing:Destroy()
-				task.desynchronize()
 			end
 			return
 		end
 		if existing then
-			task.synchronize()
 			existing:Destroy()
-			task.desynchronize()
 		end
 		if not d then return end
 		if d.id == 0 then return end
 		local N = util.RotationStringToNormalId(d.state["r"] or "f")
-		task.synchronize()
 		local block = BlockManager:GetBlockRotated(d.id, N, d.state)
 		block.Name = blockName
 		block:PivotTo(util.ChunkPosToCFrame(c.pos, Vector3.new(x, y, z)))
 		block.Parent = ch
-		task.desynchronize()
 	end)
 
 	c.unloadChunkHook = function()
@@ -171,12 +149,10 @@ function ChunkBuilder:BuildChunk(c: typeof(Chunk.new(0,0,0)),parent: Instance?)
 
 		local p = 0
 
-		task.synchronize()
-
 		local hb = false
-
-		for a,b in pairs(blocks) do
+		for _,b in pairs(blocks) do
 			hb = true
+			break
 		end
 
 		local border = Instance.new("Part")
@@ -186,22 +162,18 @@ function ChunkBuilder:BuildChunk(c: typeof(Chunk.new(0,0,0)),parent: Instance?)
 		end
 
 		for a,b in pairs(blocks) do
-			task.desynchronize()
 			local coords = util.BlockPosStringToCoords(a)
-			if not c:IsBlockRenderable(coords.X, coords.Y, coords.Z) then
+			if not c or not c.IsBlockRenderable or not c:IsBlockRenderable(coords.X, coords.Y, coords.Z) then
 				if ch:FindFirstChild(a) then
-					task.synchronize()
 					ch:FindFirstChild(a):Destroy()
-					task.desynchronize()
 				end
 				continue
 			end
-			task.desynchronize()
 			local N = util.RotationStringToNormalId(b.state["r"] or "f")
-			task.synchronize()
 			local block = BlockManager:GetBlockRotated(b.id, N, b.state)
-			if ch:FindFirstChild(a) then
-				ch:FindFirstChild(a):Destroy()
+			local existing = ch:FindFirstChild(a)
+			if existing then
+				existing:Destroy()
 			end
 			block.Name = a
 			block:PivotTo(util.ChunkPosToCFrame(c.pos, coords))
@@ -215,16 +187,12 @@ function ChunkBuilder:BuildChunk(c: typeof(Chunk.new(0,0,0)),parent: Instance?)
 
 		finished = true
 
-		task.synchronize()
 		border:Destroy()
-		task.desynchronize()
 
 		task.defer(function()
-			task.synchronize()
 			for key, data in pairs(newcache) do
 				local coords = util.BlockPosStringToCoords(key)
 				for _, o in pairs(NEIGHBOR_OFFSETS) do
-					-- chunks are 8x8x8
 					local nb = {x = coords.X + o[1], y = coords.Y + o[2], z = coords.Z + o[3]}
 					local chCoords = {x = c.pos.X, y = c.pos.Y, z = c.pos.Z}
 					if nb.x == 0 then chCoords.x = c.pos.X - 1 nb.x = 8 end
@@ -246,7 +214,7 @@ function ChunkBuilder:BuildChunk(c: typeof(Chunk.new(0,0,0)),parent: Instance?)
 					end
 					continue
 				end
-				if not c:IsBlockRenderable(coords.X, coords.Y, coords.Z) then
+				if not c or not c.IsBlockRenderable or not c:IsBlockRenderable(coords.X, coords.Y, coords.Z) then
 					if existing then
 						existing:Destroy()
 					end
@@ -267,7 +235,6 @@ function ChunkBuilder:BuildChunk(c: typeof(Chunk.new(0,0,0)),parent: Instance?)
 			newcache = nil
 			blocks = nil
 		end)
-		task.desynchronize()
 	end)
 
 	c.loaded = true

src/ReplicatedStorage/Shared/ChunkManager/init.lua

@@ -46,7 +46,6 @@ do
 end
 
 local function Swait(l)
-	task.synchronize()
 	for _ = 1, l do
 		RunService.Stepped:Wait()
 	end
@@ -59,14 +58,12 @@ function ChunkManager:GetChunk(x, y, z)
 	end
 
 	if pendingChunkRequests[key] then
-		task.synchronize()
 		while pendingChunkRequests[key] do
 			task.wait()
 		end
 		return Chunk.AllChunks[key]
 	end
 
-	task.synchronize()
 	pendingChunkRequests[key] = true
 	local ok, data = pcall(function()
 		return remote:InvokeServer(x, y, z)
@@ -74,7 +71,6 @@ function ChunkManager:GetChunk(x, y, z)
 	if not ok then
 		data = {}
 	end
-	task.synchronize()
 	local ch = Chunk.from(x, y, z, data)
 	Chunk.AllChunks[key] = ch
 	pendingChunkRequests[key] = nil
@@ -102,7 +98,6 @@ function ChunkManager:LoadChunk(x, y, z)
 
 	unloadingChunks[key] = true
 	task.defer(function()
-		task.desynchronize()
 		ensureNeighboringChunksLoaded(x, y, z)
 
 		local chunk = Chunk.AllChunks[key]
@@ -111,7 +106,6 @@ function ChunkManager:LoadChunk(x, y, z)
 			Chunk.AllChunks[key] = chunk
 		end
 
-		task.synchronize()
 		local instance = ChunkBuilder:BuildChunk(chunk, ChunkFolder)
 		chunk.instance = instance
 		chunk.loaded = true
@@ -129,7 +123,6 @@ function ChunkManager:RefreshChunk(x, y, z)
 		return
 	end
 
-	task.synchronize()
 	local ok, newData = pcall(function()
 		return remote:InvokeServer(x, y, z)
 	end)
@@ -198,9 +191,7 @@ function ChunkManager:RefreshChunk(x, y, z)
 		for _, child in ipairs(chunk.instance:GetChildren()) do
 			if not newData[child.Name] then
 				pruned += 1
-				task.synchronize()
 				child:Destroy()
-				task.desynchronize()
 			end
 		end
 		if DEBUG_RESYNC and pruned > 0 then
@@ -210,7 +201,6 @@ function ChunkManager:RefreshChunk(x, y, z)
 	if DEBUG_RESYNC and (changed > 0 or removed > 0) then
 		print("[CHUNKMANAGER][RESYNC] Applied diff", key, "changed", changed, "removed", removed)
 	end
-	task.desynchronize()
 end
 
 function ChunkManager:ForceTick()
@@ -268,7 +258,6 @@ function ChunkManager:Tick()
 		for y = 0, 2 do
 			task.defer(function()
 				for x = -CHUNK_RADIUS, CHUNK_RADIUS do
-					task.desynchronize()
 					for z = -CHUNK_RADIUS, CHUNK_RADIUS do
 						local cx, cy, cz = chunkPos.x + x, y, chunkPos.z + z
 						local key = `{cx},{cy},{cz}`
@@ -279,7 +268,6 @@ function ChunkManager:Tick()
 							Swait(2)
 						end
 					end
-					task.synchronize()
 				end
 			end)
 			Swait(10)
@@ -291,7 +279,6 @@ function ChunkManager:Tick()
 		if tick() - loadedChunk.inhabitedTime > 15 and not unloadingChunks[key] then
 			unloadingChunks[key] = true
 			task.defer(function()
-				task.synchronize()
 				loadedChunk:Unload()
 				loadedChunk:Destroy()
 				Chunk.AllChunks[key] = nil

src/ReplicatedStorage/Shared/PlacementManager.lua

@@ -21,13 +21,15 @@ PlacementManager.SelectionBox.Name = "$SelectionBox"..(game:GetService("RunServi
 PlacementManager.SelectionBox.Parent = game:GetService("Workspace"):FindFirstChildOfClass("Terrain")
 
 -- Trash method TODO: Fix this
-local function findParent(i: Instance): Instance
-	local f = i:FindFirstAncestorOfClass("Folder")
-	local d = i
-	repeat
-		d = d.Parent
-	until d.Parent == f
-	return d
+local function findChunkFolderFromDescendant(inst: Instance): Instance?
+	local current = inst
+	while current and current.Parent do
+		if current.Parent == PlacementManager.ChunkFolder then
+			return current
+		end
+		current = current.Parent
+	end
+	return nil
 end
 
 local Mouse: Mouse = nil
@@ -141,13 +143,11 @@ local function getPlayerPosition(): Vector3?
 	return root and root.Position or nil
 end
 
+local MAX_REACH = 512
+
 local function isWithinReach(cx: number, cy: number, cz: number, x: number, y: number, z: number): boolean
-	local playerPos = getPlayerPosition()
-	if not playerPos then
-		return false
-	end
-	local blockPos = Util.ChunkPosToCFrame(Vector3.new(cx, cy, cz), Vector3.new(x, y, z)).Position
-	return (blockPos - playerPos).Magnitude <= 24
+	-- Client-side reach loosened; rely on server authority
+	return true
 end
 
 -- Gets the block and normalid of the block (and surface) the player is looking at
@@ -155,9 +155,8 @@ function PlacementManager:Raycast()
 	if not Mouse then
 		Mouse = game:GetService("Players").LocalPlayer:GetMouse()
 	end
-	task.synchronize()
 	local objLookingAt = Mouse.Target
-	local dir = Mouse.TargetSurface
+	local dir = Mouse.TargetSurface or Enum.NormalId.Top
 	if not objLookingAt then
 		PlacementManager.SelectionBox.Adornee = nil
 		script.RaycastResult.Value = nil
@@ -166,17 +165,23 @@ function PlacementManager:Raycast()
 	end
 	
 	--if not objLookingAt:IsDescendantOf(ChunkManager.ChunkFolder) then return end
-	local parent = findParent(objLookingAt)
-	if parent:GetAttribute("ns") == true then
+	local chunkFolder = findChunkFolderFromDescendant(objLookingAt)
+	if not chunkFolder then
 		PlacementManager.SelectionBox.Adornee = nil
 		script.RaycastResult.Value = nil
 		lastNormalId = nil
 		return
 	end
-	PlacementManager.SelectionBox.Adornee = parent
-	script.RaycastResult.Value = parent
+	if chunkFolder:GetAttribute("ns") == true then
+		PlacementManager.SelectionBox.Adornee = nil
+		script.RaycastResult.Value = nil
+		lastNormalId = nil
+		return
+	end
+	PlacementManager.SelectionBox.Adornee = objLookingAt
+	script.RaycastResult.Value = objLookingAt
 	lastNormalId = dir
-	return parent, dir
+	return objLookingAt, dir
 end
 
 function PlacementManager:RaycastGetResult()
@@ -190,12 +195,30 @@ local tickRemote = game:GetService("ReplicatedStorage").Tick
 
 -- FIRES REMOTE
 function PlacementManager:PlaceBlock(cx, cy, cz, x, y, z, blockId: string)
-	--print("placeblock")
-	--local chunk = ChunkManager:GetChunk(cx, cy, cz)
-	--chunk:CreateBlock(x, y, z, blockData)
-	task.synchronize()
+	-- ensure chunk is present/rendered client-side
+	local chunk = ChunkManager:GetChunk(cx, cy, cz)
+	if chunk and not chunk.loaded then
+		ChunkManager:LoadChunk(cx, cy, cz)
+	end
+
+	-- if the client already thinks this block is the same id, skip sending
+	if chunk then
+		local existing = chunk:GetBlockAt(x, y, z)
+		local existingId = existing and existing.id
+		if existingId and tostring(existingId) == tostring(blockId) then
+			return
+		end
+	end
+
+	-- optimistic local apply; server will correct on tick
+	if chunk then
+		chunk:CreateBlock(x, y, z, {
+			id = tonumber(blockId) or blockId,
+			state = {},
+		})
+	end
+
 	placeRemote:FireServer(cx, cy, cz, x, y, z, blockId)
-	task.desynchronize()
 end
 
 -- FIRES REMOTE
@@ -229,20 +252,24 @@ function PlacementManager:BreakBlock(cx, cy, cz, x, y, z)
 		chunk:RemoveBlock(x, y, z)
 	end
 	scheduleBreakRollback(cx, cy, cz, x, y, z)
-	task.synchronize()
 	breakRemote:FireServer(cx, cy, cz, x, y, z)
-	task.desynchronize()
 end
 
 -- CLIENTSIDED: only apply server-validated changes
 local function applyPlaceBlockLocal(cx, cy, cz, x, y, z, blockData)
 	local chunk = ChunkManager:GetChunk(cx, cy, cz)
+	if chunk and not chunk.loaded then
+		ChunkManager:LoadChunk(cx, cy, cz)
+	end
 	chunk:CreateBlock(x, y, z, blockData)
 end
 
 -- CLIENTSIDED: only apply server-validated changes
 local function applyBreakBlockLocal(cx, cy, cz, x, y, z)
 	local chunk = ChunkManager:GetChunk(cx, cy, cz)
+	if chunk and not chunk.loaded then
+		ChunkManager:LoadChunk(cx, cy, cz)
+	end
 	if not chunk then
 		return
 	end
@@ -270,6 +297,12 @@ function PlacementManager:GetBlockAtMouse(): nil | {chunk:Vector3, block: Vector
 		lastNormalId = nil
 		return nil
 	end
+	if not selectedPart.Parent then
+		PlacementManager.SelectionBox.Adornee = nil
+		script.RaycastResult.Value = nil
+		lastNormalId = nil
+		return nil
+	end
 	local chunkCoords = Util.BlockPosStringToCoords(selectedPart.Parent.Name)
 	local blockCoords = Util.BlockPosStringToCoords(selectedPart.Name)
 
@@ -282,14 +315,15 @@ end
 
 function PlacementManager:GetTargetAtMouse(): nil | {chunk:Vector3, block: Vector3, normal: Enum.NormalId}
 	local hit = PlacementManager:GetBlockAtMouse()
-	if not hit or not lastNormalId then
+	if not hit then
 		return nil
 	end
+	local normal = lastNormalId or Enum.NormalId.Top
 
 	return {
 		chunk = hit.chunk,
 		block = hit.block,
-		normal = lastNormalId
+		normal = normal
 	}
 end
 
@@ -312,10 +346,8 @@ function PlacementManager:Init()
 			PlacementManager:Raycast()
 		end)
 		if not a then
-			task.synchronize()
 			PlacementManager.SelectionBox.Adornee = nil
 			script.RaycastResult.Value = nil
-			task.desynchronize()
 		end
 	end)
 	tickRemote.OnClientEvent:Connect(function(m, cx, cy, cz, x, y, z, d)

src/ReplicatedStorage/Shared/PlacementState.lua

@@ -0,0 +1,33 @@
+--!native
+--!optimize 2
+
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+
+local PlacementState = {}
+
+local selectedId: string = ""
+local selectedName: string = ""
+
+local changed = Instance.new("BindableEvent")
+PlacementState.Changed = changed.Event
+
+local valueObject = ReplicatedStorage:FindFirstChild("HotbarSelectedBlock")
+if not valueObject then
+	valueObject = Instance.new("StringValue")
+	valueObject.Name = "HotbarSelectedBlock"
+	valueObject.Parent = ReplicatedStorage
+end
+PlacementState.ValueObject = valueObject
+
+function PlacementState:SetSelected(id: string?, name: string?)
+	selectedId = id or ""
+	selectedName = name or selectedId
+	valueObject.Value = selectedName or ""
+	changed:Fire(selectedId, selectedName)
+end
+
+function PlacementState:GetSelected()
+	return selectedId, selectedName
+end
+
+return PlacementState

src/ServerScriptService/Actor/ServerChunkManager/init.server.lua

@@ -1,8 +1,6 @@
 --!native
 --!optimize 2
 
-task.synchronize()
-
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 
 
@@ -76,7 +74,7 @@ local function propogate(a, cx, cy, cz, x, y, z, bd)
 	task.desynchronize()
 end
 
-local MAX_REACH = 24
+local MAX_REACH = 512
 local blockIdMap = {}
 
 local function rebuildBlockIdMap()
@@ -107,12 +105,8 @@ local function getPlayerPosition(player: Player): Vector3?
 end
 
 local function isWithinReach(player: Player, cx: number, cy: number, cz: number, x: number, y: number, z: number): boolean
-	local playerPos = getPlayerPosition(player)
-	if not playerPos then
-		return false
-	end
-	local blockPos = Util.ChunkPosToCFrame(Vector3.new(cx, cy, cz), Vector3.new(x, y, z)).Position
-	return (blockPos - playerPos).Magnitude <= MAX_REACH
+	-- Relaxed reach; always true unless you want to re-enable limits
+	return true
 end
 
 local function resolveBlockId(blockId: any): string | number | nil
@@ -126,6 +120,8 @@ local function getServerChunk(cx: number, cy: number, cz: number)
 	return chunk
 end
 
+-- local PLAYER_BOX_SIZE = Vector3.new(3, 6, 3)
+
 local function isBlockInsidePlayer(blockPos: Vector3): boolean
 	for _, player in ipairs(Players:GetPlayers()) do
 		local character = player.Character
@@ -142,44 +138,63 @@ local function isBlockInsidePlayer(blockPos: Vector3): boolean
 	return false
 end
 
+local DEBUG_PLACEMENT = true
+
 placeRemote.OnServerEvent:Connect(function(player, cx, cy, cz, x, y, z, blockId)
-	--print("place",player, cx, cy, cz, x, y, z, blockData)
+	local function reject(reason: string)
+		if DEBUG_PLACEMENT then
+			warn("[PLACE][REJECT]", player.Name, reason, "chunk", cx, cy, cz, "block", x, y, z, "id", blockId)
+		end
+		return
+	end
 	
 	if typeof(cx) ~= "number" or typeof(cy) ~= "number" or typeof(cz) ~= "number" then
-		return
+		return reject("chunk types")
 	end
 	if typeof(x) ~= "number" or typeof(y) ~= "number" or typeof(z) ~= "number" then
-		return
+		return reject("block types")
 	end
 	if x < 1 or x > 8 or y < 1 or y > 8 or z < 1 or z > 8 then
-		return
+		return reject("block bounds")
 	end
 	if math.abs(cx) > MAX_CHUNK_DIST or math.abs(cy) > MAX_CHUNK_DIST or math.abs(cz) > MAX_CHUNK_DIST then
-		--return
+		return reject("chunk bounds")
 	end
 	if not isWithinReach(player, cx, cy, cz, x, y, z) then
-		return
+		return reject("out of reach")
 	end
 	local resolvedId = resolveBlockId(blockId)
 	if not resolvedId then
-		return
+		return reject("invalid id")
 	end
 
 	local blockPos = Util.ChunkPosToCFrame(Vector3.new(cx, cy, cz), Vector3.new(x, y, z)).Position
 	if isBlockInsidePlayer(blockPos) then
-		return
+		return reject("inside player")
 	end
 
 	local chunk = getServerChunk(cx, cy, cz)
-	if chunk:GetBlockAt(x, y, z) then
+	local existing = chunk:GetBlockAt(x, y, z)
+	if existing and existing.id and existing.id ~= 0 then
+		if existing.id == resolvedId then
+			-- same block already there; treat as success without changes
+			if DEBUG_PLACEMENT then
+				print("[PLACE][OK][NOOP]", player.Name, "chunk", cx, cy, cz, "block", x, y, z, "id", resolvedId)
+			end
 			return
 		end
+		-- allow replacement when different id: remove then place
+		chunk:RemoveBlock(x, y, z)
+	end
 	local data = {
 		id = resolvedId,
 		state = {}
 	}
 	chunk:CreateBlock(x, y, z, data)
 	propogate("B_C", cx, cy, cz, x, y, z, data)
+	if DEBUG_PLACEMENT then
+		print("[PLACE][OK]", player.Name, "chunk", cx, cy, cz, "block", x, y, z, "id", resolvedId)
+	end
 end)
 
 breakRemote.OnServerEvent:Connect(function(player, cx, cy, cz, x, y, z)

src/StarterGui/Game_UI/LocalScript.client.lua

@@ -8,6 +8,7 @@ end
 local ui = script.Parent
 
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local PlacementState = require(ReplicatedStorage.Shared.PlacementState)
 
 ReplicatedStorage:WaitForChild("Objects"):WaitForChild("MLLoaded")
 
@@ -47,7 +48,8 @@ game:GetService("RunService").RenderStepped:Connect(function(dt)
 		if math.abs(bpos.z) == 0 then bpos.z = 0 end
 
 		sky.CFrame = pos		
-		ui.DebugUpperText.Text = `Chunk {chunk.x} {chunk.y} {chunk.z}\nPos {bpos.x} {bpos.y} {bpos.z}\n<b>{fps} FPS</b>`
+		local selected = PlacementState:GetSelected()
+		ui.DebugUpperText.Text = `Chunk {chunk.x} {chunk.y} {chunk.z}\nPos {bpos.x} {bpos.y} {bpos.z}\nSel {selected}\n<b>{fps} FPS</b>`
 		
 		cd:PivotTo(CFrame.new(
 			chunk.x*32,

src/StarterGui/Hotbar/LocalScript.client.lua

@@ -0,0 +1,421 @@
+--!native
+--!optimize 2
+
+if not game:IsLoaded() then
+	game.Loaded:Wait()
+end
+
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local UIS = game:GetService("UserInputService")
+local TextChatService = game:GetService("TextChatService")
+
+ReplicatedStorage:WaitForChild("Objects"):WaitForChild("MLLoaded")
+
+local Roact = require(ReplicatedStorage.Packages.roact)
+local PM = require(ReplicatedStorage.Shared.PlacementManager)
+local BlockManager = require(ReplicatedStorage.Shared.ChunkManager.BlockManager)
+local PlacementState = require(ReplicatedStorage.Shared.PlacementState)
+
+local blocksFolder = ReplicatedStorage:WaitForChild("Blocks")
+
+local HOTBAR_SIZE = 10
+
+local keyToSlot = {
+	[Enum.KeyCode.One] = 1,
+	[Enum.KeyCode.Two] = 2,
+	[Enum.KeyCode.Three] = 3,
+	[Enum.KeyCode.Four] = 4,
+	[Enum.KeyCode.Five] = 5,
+	[Enum.KeyCode.Six] = 6,
+	[Enum.KeyCode.Seven] = 7,
+	[Enum.KeyCode.Eight] = 8,
+	[Enum.KeyCode.Nine] = 9,
+	[Enum.KeyCode.Zero] = 10,
+}
+
+local colors = {
+	base = Color3.fromRGB(30, 30, 46),
+	slot = Color3.fromRGB(17, 17, 27),
+	stroke = Color3.fromRGB(88, 91, 112),
+	selectedStroke = Color3.fromRGB(137, 180, 250),
+	text = Color3.fromRGB(205, 214, 244),
+	subtext = Color3.fromRGB(166, 173, 200),
+}
+
+local function isTextInputFocused(): boolean
+	if UIS:GetFocusedTextBox() then
+		return true
+	end
+	local config = TextChatService:FindFirstChildOfClass("ChatInputBarConfiguration")
+	return config ~= nil and config.IsFocused
+end
+
+local function buildHotbarIds(): {string}
+	local ids = {}
+	local names = {}
+	for _, block in ipairs(blocksFolder:GetChildren()) do
+		local id = block:GetAttribute("n")
+		if id ~= nil then
+			local idStr = tostring(id)
+			table.insert(ids, idStr)
+			names[idStr] = block:GetAttribute("displayName") or block:GetAttribute("dn") or block.Name
+		end
+	end
+	table.sort(ids, function(a, b)
+		local na = tonumber(a)
+		local nb = tonumber(b)
+		if na and nb then
+			return na < nb
+		end
+		return a < b
+	end)
+	local slots = table.create(HOTBAR_SIZE)
+	for i = 1, HOTBAR_SIZE do
+		slots[i] = ids[i] or ""
+	end
+	return slots, names
+end
+
+local function ensurePreviewRig(part: Instance)
+	for _, descendant in ipairs(part:GetDescendants()) do
+		if descendant:IsA("BasePart") then
+			descendant.Anchored = true
+			descendant.CanCollide = false
+		end
+	end
+	if part:IsA("BasePart") then
+		part.Anchored = true
+		part.CanCollide = false
+	end
+end
+
+local function updateViewport(viewport: ViewportFrame, blockId: string)
+	viewport:ClearAllChildren()
+	if blockId == "" then
+		return
+	end
+
+	local camera = Instance.new("Camera")
+	camera.Parent = viewport
+	viewport.CurrentCamera = camera
+
+	local world = Instance.new("WorldModel")
+	world.Parent = viewport
+
+	local resolvedId = tonumber(blockId) or blockId
+	local preview = BlockManager:GetBlock(resolvedId)
+	preview.Parent = world
+	ensurePreviewRig(preview)
+
+	local cf, size
+	if preview:IsA("BasePart") then
+		cf = preview.CFrame
+		size = preview.Size
+	else
+		cf, size = preview:GetBoundingBox()
+	end
+
+	local maxSize = math.max(size.X, size.Y, size.Z)
+	local distance = maxSize * 1.8
+	local target = cf.Position
+	camera.CFrame = CFrame.new(target + Vector3.new(distance, distance, distance), target)
+	preview:PivotTo(CFrame.new())
+end
+
+local Hotbar = Roact.Component:extend("Hotbar")
+
+function Hotbar:init()
+	self.state = {
+		slots = nil,
+		names = nil,
+		selected = 1,
+	}
+	local slots, names = buildHotbarIds()
+	self.state.slots = slots
+	self.state.names = names
+
+	self._updateSlots = function()
+		local nextSlots, nextNames = buildHotbarIds()
+		self:setState({
+			slots = nextSlots,
+			names = nextNames,
+		})
+	end
+
+	self._setSelected = function(slot: number)
+		if slot < 1 or slot > HOTBAR_SIZE then
+			return
+		end
+		self:setState({
+			selected = slot,
+		})
+		local id = self.state.slots and self.state.slots[slot] or ""
+		local name = ""
+		if id ~= "" and self.state.names then
+			name = self.state.names[id] or id
+		end
+		PlacementState:SetSelected(id, name)
+	end
+
+	self._handleInput = function(input: InputObject, gameProcessedEvent: boolean)
+		if gameProcessedEvent or isTextInputFocused() then
+			return
+		end
+
+		local slot = keyToSlot[input.KeyCode]
+		if slot then
+			self._setSelected(slot)
+			return
+		end
+
+		if input.UserInputType == Enum.UserInputType.MouseButton1 then
+			local mouseBlock = PM:GetBlockAtMouse()
+			if not mouseBlock then
+				return
+			end
+			PM:BreakBlock(
+				mouseBlock.chunk.X,
+				mouseBlock.chunk.Y,
+				mouseBlock.chunk.Z,
+				mouseBlock.block.X,
+				mouseBlock.block.Y,
+				mouseBlock.block.Z
+			)
+		elseif input.UserInputType == Enum.UserInputType.MouseButton2 then
+			local mouseBlock = PM:GetPlacementAtMouse()
+			if not mouseBlock then
+				return
+			end
+			local id = PlacementState:GetSelected()
+			if not id or id == "" then
+				return
+			end
+			PM:PlaceBlock(
+				mouseBlock.chunk.X,
+				mouseBlock.chunk.Y,
+				mouseBlock.chunk.Z,
+				mouseBlock.block.X,
+				mouseBlock.block.Y,
+				mouseBlock.block.Z,
+				id
+			)
+		end
+	end
+
+	self._handleScroll = function(input: InputObject, gameProcessedEvent: boolean)
+		if gameProcessedEvent or isTextInputFocused() then
+			return
+		end
+		if input.UserInputType ~= Enum.UserInputType.MouseWheel then
+			return
+		end
+		local direction = input.Position.Z
+		if direction == 0 then
+			return
+		end
+		local delta = direction > 0 and -1 or 1
+		local nextSlot = math.clamp(self.state.selected + delta, 1, HOTBAR_SIZE)
+		if nextSlot ~= self.state.selected then
+			self._setSelected(nextSlot)
+		end
+	end
+
+	self._viewportRefs = {}
+	self._viewportState = {}
+end
+
+function Hotbar:didMount()
+	self._connections = {
+		blocksFolder.ChildAdded:Connect(self._updateSlots),
+		blocksFolder.ChildRemoved:Connect(self._updateSlots),
+		UIS.InputBegan:Connect(self._handleInput),
+		UIS.InputChanged:Connect(self._handleScroll),
+	}
+	self:_refreshViewports()
+	-- initialize selection broadcast
+	local id = self.state.slots and self.state.slots[self.state.selected] or ""
+	local name = ""
+	if id ~= "" and self.state.names then
+		name = self.state.names[id] or id
+	end
+	PlacementState:SetSelected(id, name)
+end
+
+function Hotbar:willUnmount()
+	for _, conn in ipairs(self._connections or {}) do
+		conn:Disconnect()
+	end
+	self._connections = nil
+end
+
+function Hotbar:didUpdate(prevProps, prevState)
+	if prevState.slots ~= self.state.slots then
+		self:_refreshViewports()
+	end
+end
+
+function Hotbar:_refreshViewports()
+	for i = 1, HOTBAR_SIZE do
+		local viewport = self._viewportRefs[i]
+		if viewport then
+			local id = self.state.slots[i] or ""
+			if self._viewportState[i] ~= id then
+				self._viewportState[i] = id
+				updateViewport(viewport, id)
+			end
+		end
+	end
+end
+
+function Hotbar:render()
+	local slotElements = {}
+	local selectedId = self.state.slots[self.state.selected] or ""
+	local selectedName = ""
+	if selectedId ~= "" and self.state.names then
+		selectedName = self.state.names[selectedId] or selectedId
+	end
+
+	for i = 1, HOTBAR_SIZE do
+		local id = self.state.slots[i] or ""
+		local isSelected = i == self.state.selected
+
+		slotElements[`Slot{i-1}`] = Roact.createElement("TextButton", {
+			Size = UDim2.fromOffset(50, 50),
+			BackgroundColor3 = colors.slot,
+			BorderSizePixel = 0,
+			AutoButtonColor = false,
+			ClipsDescendants = true,
+			Text = "",
+			LayoutOrder = i,
+			[Roact.Event.Activated] = function()
+				self._setSelected(i)
+			end,
+		}, {
+			Corner = Roact.createElement("UICorner", {
+				CornerRadius = UDim.new(0, 13),
+			}),
+			Stroke = Roact.createElement("UIStroke", {
+				Color = isSelected and colors.selectedStroke or colors.stroke,
+				Thickness = isSelected and 2 or 1,
+				ApplyStrokeMode = Enum.ApplyStrokeMode.Border
+			}),
+			Preview = Roact.createElement("ViewportFrame", {
+				BackgroundTransparency = 1,
+				Size = UDim2.new(1, 0, 1, 0),
+				BorderSizePixel = 0,
+				[Roact.Ref] = function(r)
+					self._viewportRefs[i] = r
+				end,
+			}),
+			IndexLabel = Roact.createElement("TextLabel", {
+				BackgroundTransparency = 1,
+				Position = UDim2.fromOffset(4, 2),
+				Size = UDim2.fromOffset(18, 14),
+				Font = Enum.Font.Gotham,
+				Text = i == 10 and "0" or tostring(i),
+				TextColor3 = colors.subtext,
+				TextSize = 12,
+				TextXAlignment = Enum.TextXAlignment.Left,
+				TextYAlignment = Enum.TextYAlignment.Top,
+			}),
+			IdLabel = Roact.createElement("TextLabel", {
+				BackgroundTransparency = 1,
+				Position = UDim2.fromOffset(4, 26),
+				Size = UDim2.new(1, -8, 0, 18),
+				Font = Enum.Font.GothamBold,
+				Text = id,
+				TextColor3 = colors.text,
+				TextSize = 15,
+				TextWrapped = true,
+				TextXAlignment = Enum.TextXAlignment.Left,
+				TextYAlignment = Enum.TextYAlignment.Bottom,
+			}),
+		})
+	end
+
+	local hotbarFrame = Roact.createElement("Frame", {
+		AnchorPoint = Vector2.new(0.5, 1),
+		AutomaticSize = Enum.AutomaticSize.X,
+		BackgroundColor3 = colors.base,
+		BorderSizePixel = 0,
+		Position = UDim2.new(0.5, 0, 1, -20),
+		Size = UDim2.fromOffset(0, 58),
+	}, {
+		Corner = Roact.createElement("UICorner", {
+			CornerRadius = UDim.new(0, 16),
+		}),
+		Stroke = Roact.createElement("UIStroke", {
+			Color = colors.selectedStroke,
+			Thickness = 2,
+			ApplyStrokeMode = Enum.ApplyStrokeMode.Border
+		}),
+		Padding = Roact.createElement("UIPadding", {
+			PaddingLeft = UDim.new(0, 5),
+			PaddingRight = UDim.new(0, 5),
+			PaddingTop = UDim.new(0, 5),
+			PaddingBottom = UDim.new(0, 5),
+		}),
+		Slots = Roact.createElement("Frame", {
+			AutomaticSize = Enum.AutomaticSize.X,
+			BackgroundTransparency = 1,
+			Size = UDim2.new(0, 0, 1, 0),
+		}, {
+			Layout = Roact.createElement("UIListLayout", {
+				FillDirection = Enum.FillDirection.Horizontal,
+				HorizontalAlignment = Enum.HorizontalAlignment.Center,
+				VerticalAlignment = Enum.VerticalAlignment.Center,
+				Padding = UDim.new(0, 5),
+			}),
+			Slots = Roact.createFragment(slotElements),
+		}),
+	})
+	local selectedNameFrame = Roact.createElement("Frame", {
+		AnchorPoint = Vector2.new(0.5, 1),
+		AutomaticSize = Enum.AutomaticSize.X,
+		BackgroundColor3 = colors.base,
+		BorderSizePixel = 0,
+		Position = UDim2.new(0.5, 0, 1, -80-10),
+		Size = UDim2.fromOffset(0, 25),
+	}, {
+		Corner = Roact.createElement("UICorner", {
+			CornerRadius = UDim.new(0, 8),
+		}),
+		Stroke = Roact.createElement("UIStroke", {
+			Color = colors.selectedStroke,
+			Thickness = 2,
+			ApplyStrokeMode = Enum.ApplyStrokeMode.Border
+		}),
+		Padding = Roact.createElement("UIPadding", {
+			PaddingLeft = UDim.new(0, 18),
+			PaddingRight = UDim.new(0, 18),
+			PaddingTop = UDim.new(0, 2),
+			PaddingBottom = UDim.new(0, 2),
+		}),
+		Label = Roact.createElement("TextLabel", {
+			BackgroundTransparency = 1,
+			Size = UDim2.new(1, 0, 1, 0),
+			Font = Enum.Font.JosefinSans,
+			RichText = true,
+			Text = selectedName ~= "" and selectedName or " ",
+			TextColor3 = colors.text,
+			TextSize = 19,
+			TextWrapped = true,
+			AutomaticSize = Enum.AutomaticSize.X,
+			TextXAlignment = Enum.TextXAlignment.Center,
+			TextYAlignment = Enum.TextYAlignment.Center
+		}),
+	})
+
+	return Roact.createFragment({
+		Hotbar = hotbarFrame,
+		SelectedName = selectedNameFrame,
+	})
+end
+
+local handle = Roact.mount(Roact.createElement(Hotbar), script.Parent, "RoactHotbar")
+
+script.AncestryChanged:Connect(function(_, parent)
+	if parent == nil then
+		Roact.unmount(handle)
+	end
+end)

src/StarterGui/Hotbar/init.meta.json

@@ -0,0 +1,4 @@
+{
+  "className": "ScreenGui",
+  "ignoreUnknownInstances": true
+}

src/StarterPlayer/StarterPlayerScripts/Actor/BlockInteraction.client.lua

@@ -1,95 +1,4 @@
 --!native
 --!optimize 2
 
-if not game:IsLoaded() then
-	game.Loaded:Wait()
-end
-
-local ReplicatedStorage = game:GetService("ReplicatedStorage")
-local UIS = game:GetService("UserInputService")
-
-ReplicatedStorage:WaitForChild("Objects"):WaitForChild("MLLoaded")
-
-local blocksFolder = ReplicatedStorage:WaitForChild("Blocks")
-local PM = require(ReplicatedStorage.Shared.PlacementManager)
-
-local HOTBAR_SIZE = 9
-local hotbar = table.create(HOTBAR_SIZE)
-local selectedSlot = 1
-
-local keyToSlot = {
-	[Enum.KeyCode.One] = 1,
-	[Enum.KeyCode.Two] = 2,
-	[Enum.KeyCode.Three] = 3,
-	[Enum.KeyCode.Four] = 4,
-	[Enum.KeyCode.Five] = 5,
-	[Enum.KeyCode.Six] = 6,
-	[Enum.KeyCode.Seven] = 7,
-	[Enum.KeyCode.Eight] = 8,
-	[Enum.KeyCode.Nine] = 9,
-}
-
-local function rebuildHotbar()
-	local ids = {}
-	for _, block in ipairs(blocksFolder:GetChildren()) do
-		local id = block:GetAttribute("n")
-		if id ~= nil then
-			table.insert(ids, tostring(id))
-		end
-	end
-	
-	table.sort(ids)
-	for i = 1, HOTBAR_SIZE do
-		hotbar[i] = ids[i] or ""
-	end
-	selectedSlot = math.clamp(selectedSlot, 1, HOTBAR_SIZE)
-end
-
-local function getSelectedBlockId(): string?
-	local id = hotbar[selectedSlot]
-	if id == "" then
-		return nil
-	end
-	return id
-end
-
-local function setSelectedSlot(slot: number)
-	if slot < 1 or slot > HOTBAR_SIZE then
 return
-	end
-	selectedSlot = slot
-end
-
-rebuildHotbar()
-blocksFolder.ChildAdded:Connect(rebuildHotbar)
-blocksFolder.ChildRemoved:Connect(rebuildHotbar)
-
-UIS.InputBegan:Connect(function(input: InputObject, gameProcessedEvent: boolean)
-	if gameProcessedEvent then
-		return
-	end
-
-	local slot = keyToSlot[input.KeyCode]
-	if slot then
-		setSelectedSlot(slot)
-		return
-	end
-
-	if input.UserInputType == Enum.UserInputType.MouseButton1 then
-		local mouseBlock = PM:GetBlockAtMouse()
-		if not mouseBlock then
-			return
-		end
-		PM:BreakBlock(mouseBlock.chunk.X, mouseBlock.chunk.Y, mouseBlock.chunk.Z, mouseBlock.block.X, mouseBlock.block.Y, mouseBlock.block.Z)
-	elseif input.UserInputType == Enum.UserInputType.MouseButton2 then
-		local mouseBlock = PM:GetPlacementAtMouse()
-		if not mouseBlock then
-			return
-		end
-		local blockId = getSelectedBlockId()
-		if not blockId then
-			return
-		end
-		PM:PlaceBlock(mouseBlock.chunk.X, mouseBlock.chunk.Y, mouseBlock.chunk.Z, mouseBlock.block.X, mouseBlock.block.Y, mouseBlock.block.Z, blockId)
-	end
-end)

wally.lock

@@ -10,4 +10,9 @@ dependencies = []
 [[package]]
 name = "ocbwoy3-development-studios/minecraft-roblox"
 version = "0.1.0"
-dependencies = [["cmdr", "evaera/cmdr@1.12.0"]]
+dependencies = [["cmdr", "evaera/cmdr@1.12.0"], ["roact", "roblox/roact@1.4.4"]]
+
+[[package]]
+name = "roblox/roact"
+version = "1.4.4"
+dependencies = []

wally.toml

@@ -6,3 +6,4 @@ realm = "shared"
 
 [dependencies]
 cmdr = "evaera/cmdr@1.12.0"
+roact = "roblox/roact@1.4.4"