How would i find a part's positon relative to its model parent?

[officerv]

I want to tween all the parts of a model to a certain position while keeping their relative position to the model and their shape. Although the parts tween successfully, they do not retain their shape.
I have attempted welding, ToObjectSpace, and subtracting the model’s position by the part’s position.

Whats happening in game:

Here’s my code:

function placementModule.Start(sentModel)
	-- Check if the player is already placing something
	if currentlyPlacing then
		-- If so, return an error message and exit the function
		error('Error 001: The player is already placing an object. If you believe this is incorrect, please file a report with the error code.')
		return
	end

	-- If the player is not currently placing anything, set the currentlyPlacing variable to true
	currentlyPlacing = true

	-- Check if the desired model exists in ReplicatedStorage
	local repStorage = game:GetService('ReplicatedStorage')
	if not repStorage.models:FindFirstChild(sentModel) then
		-- If it doesn't, return an error message and exit the function
		error('Error 002: No model in rep stor. If you believe this is incorrect, please file a report with the error code.')
		return
	end

	-- Clone the desired model from ReplicatedStorage to the Workspace
	local newModel = repStorage.models[sentModel]:Clone()
	newModel.Parent = game.Workspace
	newModel.PrimaryPart = newModel:FindFirstChild('Hitbox')

	-- Begin a loop that will run as long as the player is still placing the model
	while currentlyPlacing do
		-- Wait for the next RenderStepped event
		game:GetService('RunService').RenderStepped:Wait()

		-- Use a function called startRaycast to perform a raycast and get the result
		local rayResult = placementModule.startRaycast(newModel)

		-- If the raycast hit something, check if it hit the designated placement area
		if rayResult and rayResult.Instance == game.Workspace.placementArea then
			-- Calculate the position of the model in grid units
			local gridPos = Vector3.new(
				math.floor(rayResult.Position.X / gridStud) * gridStud,
				rayResult.Position.Y + (newModel.Hitbox.Size.Y / 2),
				math.floor(rayResult.Position.Z / gridStud) * gridStud
			)
			local gridCFrame = CFrame.new(gridPos)

			-- If the model is outside the grid boundaries, do nothing
			if math.abs(gridPos.X) > 44 or math.abs(gridPos.Z) > 44 then
				--Do nothing
			end

			-- Otherwise, move the Hitbox to the calculated grid position
			newModel.Hitbox.Position = gridPos

			-- Loop through all the parts of the model and tween their positions to the grid position
			for _, part in pairs(newModel:GetDescendants()) do
				if part:IsA('Part') then
					part.CanCollide = false
					if part.Name ~= 'Hitbox' then
						local tweenInfo = TweenInfo.new(
							0.2,
							Enum.EasingStyle.Linear,
							Enum.EasingDirection.InOut
						)

						local tween = game:GetService('TweenService'):Create(part, tweenInfo, {Position = gridPos})
						tween:Play()
					end
				end
			end
		end
	end
end

[Rooilo0]

I think that the best thing you can do for it is welding. Since you don’t need complex welds, you can just use Weld Constraints (Too easy to use). You can keep the PrimaryPart of the model anchored and the rest anchored. You will be able to just move the Primary part and the rest will auto move. If I understand (my english is a trash) good the problem, I think that this will help you.

[officerv]

Thank you, but I have already found a solution. Instead, I retried with ‘toObjectSpace.’ I guess I wasn’t using it correctly. I am sorry to have wasted your time.