Hey guys! I hope you all do very very well! Being direct, I was testing a script of inverse kinematics, but I got I problem, and It’s that when the block goes way too far from the character’s body, it’s arm goes away with it:
-Here’s the video:
I don’t really know how to fix this, and I’ll be very very VERY grateful with you and your heart if you can give me a hand with this, I don’t really know how to fix this, thanks for reading and have a nice day! 
My goal is to make the arm move with inverse kinematics to where it’s this red block but without quitting the character’s shoulder position.
Something like this:
-Here’s the script (ServerScript):
local pi =math.pi
local halfpi =pi/2
local forwardV3 =Vector3.new(0,0,-1) -- Constant
--[[
OriginCFrame is the CF of the shoulder joint, this can be gotten using some CFrame:
upperTorso.CFrame * shoulderJoint.C0
Note that the shoulderJoint.C0 would be the INITIAL shoulderJoint C0, before anything has been done
targetPos is the target Position you are trying to point to, this will be a Vector3 in the world space
a is the length of the upper arm, I use 0.515
b is the length of the lower arm + the hand, I use 1.1031
--]]
local function solveArm(originCFrame,targetPosition,a,b)
-- Localize the targetPosition in regards to originCFrame
local localized = originCFrame:pointToObjectSpace(targetPosition)
local localizedUnit = localized.unit
-- Construct a CFrame pointing from the shoulder position to the target position
local axis = forwardV3:Cross(localizedUnit)
local angle = math.acos(-localizedUnit.Z)
local plane = originCFrame*CFrame.fromAxisAngle(axis,angle)
-- Get the length from the origin to our target position
local c = localized.Magnitude
-- If c is between the lengths of a and b then return an offsetted plane so that one of the lengths reaches the goal,
-- but the other length is folded so it looks natural
if c < math.max(a,b)-math.min(a,b) then
return plane * CFrame.new(0,0,math.max(b,a)-math.min(b-a)-c), -halfpi, pi
-- If c > a + b then return flat angles and an offsetted plane which reaches its target
elseif c > a+b then
return plane * CFrame.new(0,0,a+b-c), halfpi, 0
-- Otherwise, use the law of cosines
else
local theta1 = -math.acos((-(b * b) + (a * a) + (c * c)) / (2 * a * c)) -- law of cosines, gets the angle opposite b
local theta2 = math.acos(((b * b) - (a * a) + (c * c)) / (2 * b * c)) -- law of cosines, gets the angle opposite a
return plane, theta1 + halfpi, theta2 - theta1
end
end
-- Demonstration for how this can be called:
local targetObj =workspace:WaitForChild("Target")
local character =workspace:WaitForChild("Test")
local upperTorso =character:WaitForChild("UpperTorso")
local rightUpperArm =character:WaitForChild("RightUpperArm")
local rightLowerArm =character:WaitForChild("RightLowerArm")
local rightShoulder =rightUpperArm:WaitForChild("RightShoulder")
local rightElbow =rightLowerArm:WaitForChild("RightElbow")
local rightShoulderInit =rightShoulder.C0 -- This can be a preset value, since it will always be the same, it is the offset from the UpperTorso to the RightShoulder joint
local rightElbowInit =rightElbow.C0 -- This can be a preset value, since it will always be the same, it is the offset from the RightUpperArm to the RightElbow joint
local tp0 =CFrame.new((upperTorso.CFrame * CFrame.new(1.25,0,-1)).p)*CFrame.Angles(0,math.pi/2,0)
while wait() do
local targetPos =targetObj.Position
local shoulderCF =upperTorso.CFrame * rightShoulderInit
local plane, shoulderAngle, elbowAngle =solveArm(shoulderCF, targetPos, 0.515, 1.031)
rightShoulder.C0 =upperTorso.CFrame:toObjectSpace(plane) * CFrame.Angles(shoulderAngle, 0, 0)
rightElbow.C0 =rightElbowInit * CFrame.Angles(elbowAngle, 0, 0)
end
Even if you can give me the smallest hand, I’ll be grateful with it, thank you and byee! 
