Rounding numbers not working properly

Help and Feedback Scripting Support
#1

You can write your topic however you want, but you need to answer these questions:

  1. What do you want to achieve? Keep it simple and clear!
    I’m trying to make a placement system and every time I try to round to nearest 3. Like 3,6,9,12,15.

  2. What is the issue? Include screenshots / videos if possible!
    It works at first but when I try to round into negative numbers it doesn’t work.
    here is the script in the tool

local localplayer = game.Players.LocalPlayer
local replicatedstorage = game:GetService("ReplicatedStorage")
local event = replicatedstorage.Placed
local blocks = replicatedstorage.Blocks
local mouse = localplayer:GetMouse()
function round(n)
	return math.floor(n/3 + 0.5) * 3
end

script.Parent.Activated:Connect(function()
	local blockpl = blocks.WoodPlanks:Clone()
	blockpl.Position = Vector3.new(round(mouse.Hit.X),round(mouse.Hit.Y),round(mouse.Hit.Z))
	blockpl.Parent = game.Workspace
end)

Here is an example:
https://www.youtube.com/watch?v=FfLabu1cet4

  1. What solutions have you tried so far? Did you look for solutions on the Developer Hub?
    Yes I have looks on the devforum, but all the rounding methods just work on the addition and not negative.
2 Likes
#2 
local gridNumber(n)
   return n - (n%3)
end
1 Like
#3

doesn’t work thanks for commenting though

#4

I forgot to declare the function, if you haven’t done that, this should work.

local function gridNumber(n)
   return n - (n%3)
end
1 Like
#5

yeah i added the function before and it still doesn’t work

#6

Uhhh, I just tested it and it works perfectly for me, unless I missunderstood what you really want.

You want a number to be rounded into grid offset right? And the grid is 3 studs.

3 → 3
4 → 3
8 → 9
28 → 27

1 Like
#7

Try this:

local function round(n)
    return math.floor(n + 0.5)
end
1 Like
#8

Ok ill test it again, ill let you know how it goes

#9

Did you read my post, I used that and it didn’t work

#10

Of course, but notice that putting negative values will not give the same output as using math.round.
So here in case to make it works with negative values:

function round(x)
	if x < 0 then
		x = math.floor(x - 0.5)
	else
		x = math.floor(x + 0.5)
	end
	return x
end
2 Likes
#11

What do you mean? That’s not what you used.

1 Like
#12

just letting you know this is also meant to be a placement system

#13 
I see but I think there needs to be math.ceil if x<0 like this:
function round(x)
	if x < 0 then
		x = math.ceil(x - 0.5)
	else
		x = math.floor(x + 0.5)
	end
	return x
end
2 Likes
#14

Try with this (You might organize your code better and don’t make everything lowercase).

local replicatedstorage = game:GetService("ReplicatedStorage")

local localplayer = game:GetService("Players").LocalPlayer
local mouse = localplayer:GetMouse()

local event = replicatedstorage:WaitForChild("Placed")
local blocks = replicatedstorage:WaitForChild("Blocks")

local function round(x)
	if x < 0 then
		x = math.ceil(x - 0.5)
	else
		x = math.floor(x + 0.5)
	end
	return x
end

script.Parent.Activated:Connect(function()
	local woodplanks = blocks:WaitForChild("WoodPlanks")
	local blockpl = woodplanks:Clone()
	blockpl.Position = Vector3.new(round(mouse.Hit.X), round(mouse.Hit.Y), round(mouse.Hit.Z))
	blockpl.Parent = workspace
end)
2 Likes
#15

Yeah i just noticed that i did something wrong, but i saw that floor were almost doing the same job and i wrote it quick. Thanks correcting me.

2 Likes
#16

is this the right video now? - YouTube
ok this is the right video, its just that it places the blocks inside the block. this is a 3x3 grid not a 1x1 or 2x2 grid

1 Like
#17

I can’t test it but maybe try changing the return x inside the ‘round’ function by return x * 3.

1 Like
#18

nope just places it far away from the mouse

#19

Sorry to intervene, but why you didn’t just use math.round, it seems to work fine.

2 Likes
#20

math.round rounds to the nearest whole

1 Like