Unit of a vector multiplied by a value returns nan

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#1

I am trying to make a custom explosion modulescript, however when i try to calculate the explosion knockback it returns NaN and the player vanishes. Sometimes the math is normal and sometimes it returns NaN.

The code of the modulescript:

local explosion = {}
local TO_BE_SET = nil

local glass = require(game.ReplicatedStorage.GunEngine.Glass)
local ragmod = require(game.ServerScriptService.R6Ragdoll.ModuleScript)

function explosion:Create()
	local explosionData = {}
	explosionData.BlastRadius2 = TO_BE_SET
	explosionData.BlastPressure2 = TO_BE_SET
	explosionData.Position2 = TO_BE_SET
	explosionData.Sound2 = TO_BE_SET
	explosionData.KnockbackPower = TO_BE_SET
	print("created")
	
	return explosionData
end

local function linearDropOff(distance)
	return math.clamp(-(1/140)*(distance-20)+1.5,0.3,1.5)
end

function explosion:Explode(explosionData)
	local exp = Instance.new("Explosion")
	exp.BlastRadius = 0
	exp.BlastPressure = 0

	exp.Position = explosionData.Position2
	exp.DestroyJointRadiusPercent = 0
	exp.Visible = true
	exp.Parent = workspace

	print("exploded")

	local part = Instance.new("Part")
	part.Parent = workspace
	part.CanCollide = false
	part.Anchored = true
	part.Transparency = 1
	part.Position = explosionData.Position2
	part.Name = "ExplosionSound"
	
	for _, v in pairs(workspace:GetChildren()) do
		if v:FindFirstChild("Humanoid") then
			local hum = v:WaitForChild("Humanoid")
			local hrp = hum.Parent:WaitForChild("HumanoidRootPart")
			local char = hrp.Parent
			
			if hrp then
				if (hrp.Position - part.Position).Magnitude < explosionData.BlastRadius2 then
					if char ~= nil then
						local dist = (hrp.Position - part.Position).Magnitude
						hum.BreakJointsOnDeath = false

						hum:TakeDamage(40)
						char.RagdollTrigger.Value = true

						task.delay(10, function()
							char.RagdollTrigger.Value = false
						end)

						wait()
						local knockbackDirection = (part.Position - hrp.Position).Unit * explosionData.KnockbackPower -- this is where it returns NaN
						wait()
						print(knockbackDirection)

						local bv = Instance.new("LinearVelocity")
						bv.Parent = char.Torso

						local attachment = Instance.new("Attachment")
						attachment.Parent = hrp

						bv.MaxForce = math.huge
						bv.Attachment0 = attachment
						wait()
						bv.VectorVelocity = knockbackDirection
						wait()
						print(bv.VectorVelocity)

						game.Debris:AddItem(bv, 0.1)
					end
				end
			end
		end
	end

	local newSnd = explosionData.Sound2:Clone()
	newSnd.Parent = part
	newSnd:Play()
	local conn

	conn = newSnd.Ended:Connect(function()
		conn:Disconnect()
		newSnd:Destroy()
	end)
end

return explosion
#2

NaN means Not a Number which is a unrepresentable number.

The math you are doing may be resulting in a number that is undefined according to the code leading to NaN appearing.

#3

I am aware that NaN means Not a Number, but this does not really help fix the issue. The thing is that sometimes the result is NaN, and sometimes it works perfectly fine.

#4

I can’t see how KnockbackPower is calculated. Can you show us the code where it is calculated?