Custom Conveyor Behavior BUG [Another Solution is Welcomed]

[roadtoprobreakin (Road)]

I need help with this conveyor behavior problem

The bug is pretty weird, and RNG, it sometimes work, it sometimes doesn’t work. I don’t know what exactly caused it. I even set up a macro to do the exact something, but even that yields different result. I could place only 3 conveyors and get the bug, or place 50 without encountering it. Honestly, I’m just so tired of this.

I did modify the code below me to use fixed step for more stable delta time, move the movement logic to client side, etc. But even with that it still doesn’t work.

Previous code:

local conveyorConn = RunService.Heartbeat:Connect(function(dt)
    for _, conveyor in conveyorsDataList do
        local item = conveyor.Item
        local nextConveyor = ConveyorController.get("model", conveyor.NextConveyor)

        if item and nextConveyor and not nextConveyor.TempItem and conveyor.Elapsed < 1 then
            conveyor.Elapsed += conveyor.Speed * math.min(dt, 0.1) * textureConveyorSpeedRatio
            conveyor.TempItem = nil

            local alpha = math.clamp(conveyor.Elapsed, 0, 1)
            moveItemToNextConveyor(alpha, item, conveyor.MainModel, nextConveyor.MainModel)

            if alpha >= 1 then -- When item is fully moved then:
                nextConveyor.Item = item
                nextConveyor.TempItem = item
                conveyor.Item = nil

                conveyor.Elapsed = 0
            end
        end
    end
end)

Improved code, that still doesn’t work :

local fixedStep = 1/60
local accumulator = 0
local lastTime = time()

RunService.Heartbeat:Connect(function()
	local now = time()
	local dt = now - lastTime
	lastTime = now

	accumulator += dt

	local steps = 0
	local movesBatch = {}

	while accumulator >= fixedStep and steps < 5 do
		-- Process conveyor logic
		
		for _, conveyor in table.clone(conveyorsDataList) do
			--[[if not conveyor.Item and conveyor.TempItem then
				conveyor.TempItem:Destroy()
				conveyor.TempItem = nil
			end--]]

			local item = conveyor.Item
			local nextConveyor = ConveyorController.get("model", conveyor.NextConveyor)

			if item and nextConveyor and not nextConveyor.TempItem and conveyor.Elapsed < 1 then
				if conveyor.Elapsed == 0 then
					print("test", nextConveyor.TempItem)
					conveyor.TempItem = nil

					local okStart, startCF = pcall(function()
						return item.PrimaryPart and item.PrimaryPart.CFrame
					end)
					local okEnd, endCF = pcall(function()
						return getItemEndCFrame(item, nextConveyor.MainModel)
					end)

					local duration = (conveyor.Speed and conveyor.Speed > 0) and
						(1 / (conveyor.Speed * textureConveyorSpeedRatio)) or 1

					if okStart and okEnd and startCF and endCF then
						table.insert(movesBatch, {
							Item = item,
							Start = startCF,
							End = endCF,
							Duration = duration
						})
					end
				end

				conveyor.Elapsed = math.min(
					conveyor.Elapsed + conveyor.Speed * fixedStep * textureConveyorSpeedRatio,
					1
				)

				if conveyor.Elapsed >= 1 then
					nextConveyor.Item = item
					conveyor.Item = nil

					nextConveyor.TempItem = item
					conveyor.Elapsed = 0

					moveItemToConveyor(item, conveyor.NextConveyor)
				end
			end
		end--]]

		accumulator -= fixedStep
		steps += 1
	end

	if #movesBatch > 0 then
		pcall(function()
			RE.Conveyors.TweenItem:FireAllClients(movesBatch)
		end)
	end
end)

btw this is the logic for sending item
Example ID 1 wants to send to ID 2

check if ID2 has tempitem (not item), if no then set tempitem of ID1 to false and ID2 to true, after done moving, it will actually move the item, ID1 item = false, ID2 item = true

On normal occasion it should the progress should look like this :
{item, tempitem}

ID1 → exist exist
ID2 → nil nil

ID1 said oh alright tempitem on ID2 is nil, I’ll move my tempitem to him, and I should take a note that transferring will take time and not instant

ID1 → exist nil
ID2 → nil exist

ID1 said, ohh my time has come, alright goodbye item!

ID1 → nil nil
ID2 → exist exist

POSSIBLE BUGS? (Another Case)
Item x → moving to conveyor a
Item y → moving to conveyor b
Item z → moving to conveyor c

At the same time, it loops through every conveyor and then move item to next conveyor
ID x move to a (normal)
ID z move to c (normal)
ID y, after finish moving to b, it jumps straight to id c, and it overwrites item Z

Extra note:
f next conveyor has an item but tempitem is nil it will still move item to that conveyor, that’s what it makes the item overrides

weird conveyor bug

not hell (3).rbxl (123.3 KB)

Thanks if anyone managed to read all of this, hopefully I can fix this bug soon

[roadtoprobreakin (Road)]

oh yeah if anyone is wondering, the temp item on conveyor ID 1 shown on the table, is linked to an item on conveyor id number 3

[ShadowLogan31 (DevLog)]

I managed to fix it, the issue was the way you were handling item movement:

• With your method, you are removing the TempItem right from the start, which causes collisions.
• Secondly, it’s better to have a queue system, this way, instead of basing movement on a conveyor’s Elapsed variable, you can provide each moving item with it’s own elapsed variable, which prevents overwriting when multiple items move at the same time.

ConveyorSystem.rbxl (116.1 KB)