Raycasting Gun Spread

[Sunx_x]

Hello!
I made a gun system by using raycasting.
But I am bad at math and don’t know how to make a spread

Can someone help, please?

Source

script.Parent.CastBullet.OnServerEvent:Connect(function(plr, mouse, dmg, FirePoint, char, range)
	local ray = Ray.new(FirePoint.WorldCFrame.Position, (mouse.Position - FirePoint.WorldCFrame.Position).Unit * range)
	
	local ignore = workspace.NoRay:GetChildren();
	table.insert(ignore, plr.Character)
	
	local part, position = game.Workspace:FindPartOnRayWithIgnoreList(ray, ignore)
	
	local bullet = Instance.new("Part", workspace.NoRay)
	bullet.Name = "Bullet"
	bullet.Anchored = true
	bullet.Material = Enum.Material.Neon
	bullet.CanCollide = false
	bullet.Locked = true
	bullet.BrickColor = BrickColor.new("New Yeller")
	
	local distance = (FirePoint.WorldCFrame.Position - position).Magnitude
	bullet.Size = Vector3.new(0.1, 0.1, distance)
	bullet.CFrame = CFrame.new(FirePoint.WorldCFrame.Position, position) * CFrame.new(0, 0, - distance / 2)
	
	if part then
		local hum = part.Parent:FindFirstChild("Humanoid")
		
		if not hum then
			hum = part.Parent.Parent:FindFirstChild("Humanoid")
		end
		
		if hum then
			hum:TakeDamage(dmg)
			if part.Name == "Head" then
				hum:TakeDamage(dmg * 2)
			end
		end
	end
	
	game.Debris:AddItem(bullet, 0.1)
end)

[Operatik]

To add spread to a raycasting weapon, simply add a math.random() on the finishing position.

local SPREAD = 1000 -- set some value for it
local spreadPosition = Vector3.new(
    FirePoint.WorldCFrame.Position.X + math.random(-SPREAD, SPREAD)/1000,
    FirePoint.WorldCFrame.Position.Y + math.random(-SPREAD, SPREAD)/1000,
    FirePoint.WorldCFrame.Position.Z + math.random(-SPREAD, SPREAD)/1000
)

I reckon there was a better method.

---

Looks like parent argument of Instance.new() is here again. Do not use it.

PSA: Don't use Instance.new() with parent argument

I’ve discovered a pretty bad performance issue in one of top games that has to do with Instance.new and wanted to write about this, since this is not obvious unless you know the system inside out. Tthere are several ways to create a ROBLOX object in Lua: local obj = Instance.new(‘type’); fill obj fields local obj = Instance.new(‘type’, parent); fill obj fields local obj = util.Create(‘type’, { field1 = value1, … }) If you care at all about performance, please only use the first option - I wi…

[Sunx_x]

What do i have to do with “spreadPosition”

[Operatik]

Use that to replace the FirePoint.WorldCFrame.Position in the first line on the function:

local ray = Ray.new(FirePoint.WorldCFrame.Position, (mouse.Position - spreadPosition).Unit * range)

[Sunx_x]

local ray = Ray.new(FirePoint.WorldCFrame.Position, (mouse.Position - spreadPosition).Unit * range)

Works!!!
Thank you!

[Isosta (sosta)]

This is a bad method for spread. Adjusting based on the mouse position will lead to inaccurate spread based on range. You need to alter a unit direction rather than the final position.

[Operatik]

Already fixed it in the PMs with an alternative of creating a fixed cone-shaped spread through an alternative:

local accurateRay = Ray.new(FirePoint.WorldCFrame.Position, (mouse.Position - spreadPos).Unit * range)
local calculatedRay = Ray.new(accurateRay.Origin, CFrame.Angles(math.rad(math.random(-spreadAngle, spreadAngle)), math.rad(math.random(-spreadAngle, spreadAngle)), math.rad(math.random(-spreadAngle, spreadAngle))) * accurateRay.Direction)

[Isosta (sosta)]

mouse.Position - spreadPos

You shouldn’t be doing it like this. You need a lookVector.

[BananaThief28 (pedropaulo25471)]

How would I make the spread angle?