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Rjac 2

Rotating Joints According to Camera

What is Rjac?​

Rjac (pronounced as "r-jack") is an object-oriented module used to rotate character body parts according to camera direction.

For example:

Clip 1

Clip 2

Clip 3

Clip 4

The mechanic is used in a lot of games and module is easy to use with simplicity, flexibilty, and customization.

What's changed from Rjac 1?​

  • Support for R6 using LookVectorAxes
  • Better design
  • Cleaner code

Demo​

Try it for yourself as a player. Run around looking in different directions and your avatar's head will turn as well. Equip the gun and then even the right arm starts rotating.

Game is open for both R6 and R15 at the same time.

The .rbxl file can be downloaded from the Github repository.

https://www.roblox.com/games/124920330844766/Rjac-2-Demo

How to use it?​

As I said it's pretty simple to use but not very small, a basic example:

local Player = game:GetService("Players").LocalPlayer
local Rjac = require(game.ReplicatedStorage:WaitForChild("Rjac2"))

Player.CharacterAdded:Wait()
local Humanoid = Player.Character:WaitForChild("Humanoid")

-- R15 rig
local Configurations = {
    {
        BodyPart = "Head",
        BodyJoint = "Neck",
        MultiplierVector = Vector3.new(0.8, -0.8, 0),
        LookVectorAxes = {"Y", "X", "Z"}
    },
    {
        BodyPart = "UpperTorso",
        BodyJoint = "Waist",
        MultiplierVector = Vector3.new(0.2, -0.2, 0),
        LookVectorAxes = {"Y", "X", "Z"}
    },
    -- {
    --     BodyPart = "RightUpperArm",
    --     BodyJoint = "RightShoulder",
    --     MultiplierVector = Vector3.new(1, 0, 0),
    --     LookVectorAxes = {"Y", "X", "Z"}
    -- },
    -- {
    --     BodyPart = "LeftUpperArm",
    --     BodyJoint = "LeftShoulder",
    --     MultiplierVector = Vector3.new(1, 0, 0),
    --     LookVectorAxes = {"Y", "X", "Z"}
    -- },
}

local Profile = Rjac.new({Player = Player})
Profile:Initiate()

for _,v in pairs(Configurations) do
    Profile:AddBodyJoint(v.BodyPart, v.BodyJoint, v.MultiplierVector, v.LookVectorAxes)
end

Profile.Enabled = true

game:GetService("RunService").RenderStepped:Connect(function()
    Profile:Update(game.Workspace.CurrentCamera.CFrame)
end)

Configuration Format​

{
    BodyPart = "Head",
    BodyJoint = "Neck",
    MultiplierVector = Vector3.new(0.8, -0.8, 0),
    LookVectorAxes = {"Y", "X", "Z"}
}

Now let's break this down a bit and see what it means

  • BodyPart i.e "Head" is the name of the BasePart in the Character
  • where Rjac will find a Motor6D, named the value of BodyJoint i.e "Neck".
  • MultiplierVector is the Vector3, which determines by what value the joint will be rotated.
  • LookVectorAxes specifies which axis of CameraCFrame.LookVector affects the joint rotations

There is only one way of fully understanding how to use this, which is by experimenting with the module itself.

Documentation​

Taking a look at the Documentation is heavily encouraged to use the module to its full potential.

Some Sample Configurations​

To help developers better familiarise themselves with Rjac.

  • R6 Sample

These configurations rotate the head, arms

local Configurations = {
    {
        BodyPart = "Torso",
        BodyJoint = "Neck",
        MultiplierVector = Vector3.new(-1, 0, -1),
        LookVectorAxes = {"Y", "X", "X"}
    },
    {
        BodyPart = "Torso",
        BodyJoint = "Right Shoulder",
        MultiplierVector = Vector3.new(0, 0, 1),
        LookVectorAxes = {"Y", "X", "Y"}
    },
    {
        BodyPart = "Torso",
        BodyJoint = "Left Shoulder",
        MultiplierVector = Vector3.new(0, 0, -1),
        LookVectorAxes = {"Y", "X", "Y"}
    }
}
  • R15 Sample

These configurations rotate the head, arms, lower back

local Configurations = {
    {
        BodyPart = "Head",
        BodyJoint = "Neck",
        MultiplierVector = Vector3.new(0.8, -0.8, 0),
        LookVectorAxes = {"Y", "X", "Z"}
    },
    {
        BodyPart = "UpperTorso",
        BodyJoint = "Waist",
        MultiplierVector = Vector3.new(0.2, -0.2, 0),
        LookVectorAxes = {"Y", "X", "Z"}
    },
    {
        BodyPart = "RightUpperArm",
        BodyJoint = "RightShoulder",
        MultiplierVector = Vector3.new(1, 0, 0),
        LookVectorAxes = {"Y", "X", "Z"}
    },
    {
        BodyPart = "LeftUpperArm",
        BodyJoint = "LeftShoulder",
        MultiplierVector = Vector3.new(1, 0, 0),
        LookVectorAxes = {"Y", "X", "Z"}
    }
}

Github​

https://github.com/SohamBorate/Rjac-2

License​

Mozilla Public License 2.0

Permissions of this weak copyleft license are conditioned on making available source code of licensed files and modifications of those files under the same license (or in certain cases, one of the GNU licenses). Copyright and license notices must be preserved. Contributors provide an express grant of patent rights. However, a larger work using the licensed work may be distributed under different terms and without source code for files added in the larger work.

Read the full document here.

Installation​