Viewmodel Sway Problem

Help and Feedback Scripting Support
#1

Greetings, fellow developers! I am working on a game where you hold a flashlight with a spotlight using the new future lighting. I’m using a viewmodel to hold the flashlight and not a tool. The spotlight and flashlight look really nice, but when I move the camera around, the flashlight looks stuck on the camera. So, I want to make some sort of sway so the flashlight doesn’t look stuck on the camera. However, I don’t really know how to make sway. I think it has something to do with calculating the magnitude and lookVecter, and changing the CFrame of the viewmodel.

Here is the script for the viewmodel:

local player = game:GetService("Players").LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local camera = workspace.Camera
local runService = game:GetService("RunService")

local viewModel = game:GetService("ReplicatedStorage"):WaitForChild("ViewModel"):Clone()
viewModel.Parent = camera

runService.RenderStepped:Connect(function()
	if character:FindFirstChild("Humanoid").Health == 0 then
		if camera:FindFirstChild("ViewModel") ~= nil then
			camera.ViewModel:Destroy()
		end
	end
	if camera:FindFirstChild("ViewModel") ~= nil then
		camera.ViewModel:SetPrimaryPartCFrame(camera.CFrame * CFrame.new(0.25,-1.5,-1) * CFrame.Angles(0.05,0,0))
	end
end)

Any help will be appreciated. Thanks!

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#2

If you want sway I’d recommend using someone’s spring module or make one yourself.

1 Like
#3

SpringModule.rbxm (1.3 KB)
Here’s one that’s pretty simple to use.

It has 3 functions:

  1. SpringModule.new()
  2. Spring:shove(Vector3.new())
  3. Spring:update(dt)

You basically just create a new spring using function #1

local SwaySpring = SpringModule.new()

then you apply some shove to it, in this case whenever the mouse moves
I recommend using

game:GetService("UserInputService"):GetMouseDelta())

and then use the X and Y values for that with the :shove() function.
Finally you can then update the spring with :update(dt) and there you go.

#4

Thanks, I’ll try to see if I can make it work.

#5

Let me know if you need more help.

1 Like
#6

So, I feel like I’m getting closer, but I don’t know how to fix this error.

Players.MrFinkyDoodles.PlayerGui.LocalScript:24: attempt to call a nil value

Here is my script:

local runService = game:GetService("RunService")
local replicatedStorage = game:GetService("ReplicatedStorage")
local userInputService = game:GetService("UserInputService")

local modules = replicatedStorage:WaitForChild("Modules")
local SpringModule = require(modules:FindFirstChild("SpringModule"))

local player = game:GetService("Players").LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local camera = workspace.Camera
local viewModel = game:GetService("ReplicatedStorage"):WaitForChild("ViewModel"):Clone()
viewModel.Parent = camera

runService.RenderStepped:Connect(function()
	if character:FindFirstChild("Humanoid").Health == 0 then
		if camera:FindFirstChild("ViewModel") ~= nil then
			camera.ViewModel:Destroy()
		end
	end
	if camera:FindFirstChild("ViewModel") ~= nil then
		camera.ViewModel:SetPrimaryPartCFrame(camera.CFrame * CFrame.new(0.25,-1.5,-1) * CFrame.Angles(0.05,0,0))
		
		local mouseDelta = userInputService:GetMouseDelta()
		SpringModule:shove(Vector3.new(-mouseDelta.X / 500,mouseDelta.Y / 200,0)) --line with error
		local updatedSpring = SpringModule:update(dt)
		
		viewModel:FindFirstChild("HumanoidRootPart").CFrame *= CFrame.new(updatedSpring.X,updatedSpring.Y,0)
	end
end)

Thanks for the help!

#7

Ok ok, so you have gotten the SpringModule but then haven’t created the spring. Instead you are calling for the module itself which is incorrect.

Try:

local Sway = SpringModule.new()

and then only refer to “Sway” in your renderstepped function.

1 Like
#8

I got another error:

attempt to perform arithmetic (mul) on nil and number

This error was in the springModule:

-- Constants

local ITERATIONS	= 8

-- Module

local SPRING	= {}

-- Functions 

function SPRING.new(self, mass, force, damping, speed)

	local spring	= {
		Target		= Vector3.new();
		Position	= Vector3.new();
		Velocity	= Vector3.new();

		Mass		= mass or 5;
		Force		= force or 50;
		Damping		= damping or 4;
		Speed		= speed  or 4;
	}

	function spring.getstats(self)
		return self.Mass, self.Force, self.Damping, self.Speed
	end

	function spring.changestats(self, mass, force, damping, speed)
		self.Mass = mass or self.Mass
		self.Force = force or self.Force
		self.Damping = damping or self.Damping
		self.Speed = speed or self.Speed
	end

	function spring.shove(self, force)
		local x, y, z	= force.X, force.Y, force.Z
		if x ~= x or x == math.huge or x == -math.huge then
			x	= 0
		end
		if y ~= y or y == math.huge or y == -math.huge then
			y	= 0
		end
		if z ~= z or z == math.huge or z == -math.huge then
			z	= 0
		end
		self.Velocity	= self.Velocity + Vector3.new(x, y, z)
	end

	function spring.update(self, dt)
		local scaledDeltaTime = dt * self.Speed / ITERATIONS -- line with error
		for i = 1, ITERATIONS do
			local iterationForce= self.Target - self.Position
			local acceleration	= (iterationForce * self.Force) / self.Mass

			acceleration		= acceleration - self.Velocity * self.Damping

			self.Velocity	= self.Velocity + acceleration * scaledDeltaTime
			self.Position	= self.Position + self.Velocity * scaledDeltaTime
		end

		return self.Position
	end

	return spring
end

-- Return

return SPRING
#9

I think that’s because you attempted to update the spring by “dt” which you haven’t defined. “dt” stands for deltatime and can be defined inside the brackets of the renderstepped function:

runService.RenderStepped:Connect(function(dt)

Try that and see if it works, if not, send me a model file or place file and I’ll debug it myself.

#10

Here is a place file:
swayTroubles.rbxl (133.3 KB)

#11 
local player = game:GetService("Players").LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local camera = workspace.Camera
local runService = game:GetService("RunService")

local viewModel = game:GetService("ReplicatedStorage"):WaitForChild("ViewModel"):Clone()
viewModel.Parent = camera

local swayEffect=.7
local swayCFrame=CFrame.new()
local lastCamCFrame=CFrame.new()

runService.RenderStepped:Connect(function()
	if character:FindFirstChild("Humanoid").Health == 0 then
		if camera:FindFirstChild("ViewModel") ~= nil then
			camera.ViewModel:Destroy()
		end
	end
	if camera:FindFirstChild("ViewModel") ~= nil then

local rotation=camera.CFrame:ToObjectSpace(lastCamCFrame)
local X,Y,Z=rotation:ToOrientation()
swayCFrame=swayCFrame:Lerp(CFrame.Angles(math.sin(X)*swayEffect,math.sin(Y)*swayEffect,0),.1)

lastCamCFrame=camera.CFrame
		camera.ViewModel:SetPrimaryPartCFrame(camera.CFrame *swayCFrame*CFrame.new(0.25,-1.5,-1))
	end
end)
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