I am making an obby stage where there are Rocks falling from the ceiling and you have to get through before it kills you when you touch the so called “Smash Part” of the rock

I welded the two part together with a weld constraint:

but the “SmashPart” is not anchored:

I am lerping the rocks to fall and rise again. I have selected Part1 and Part2 correctly:

and I believe I set up the SmashPart correctly (see the second screenshot). But instead they are floating in mid-air like in the build mode. My script to move the Stones is here:

local Library = require(game:GetService("ServerScriptService"):WaitForChild("Library"))
local Rocks = script.Parent:WaitForChild("Rocks"):GetChildren()

local moveDownDistance = 20


for _, Rock in ipairs(Rocks) do

    local originalPosition = Rock.Position
    local targetPosition = originalPosition - Vector3.new(0, moveDownDistance, 0)
    local moveDownTime = 1.5
    local riseTime = 2.3

    task.spawn(function()
        while true do
            local startTime = tick()
            while tick() - startTime < moveDownTime do
                local elapsedTime = tick() - startTime
                local lerpedPosition = originalPosition:Lerp(targetPosition, elapsedTime / moveDownTime)
                Rock.Position = lerpedPosition
                task.wait()
            end

            task.wait(2)

            startTime = tick()
            while tick() - startTime < riseTime do
                local elapsedTime = tick() - startTime
                local lerpedPosition = targetPosition:Lerp(originalPosition, elapsedTime / riseTime)
                Rock.Position = lerpedPosition
                task.wait()
            end

            task.wait(1)
        end
    end)
    task.wait(1.5)
end

Doesn’t welding work for lerping?