How to get the edge of a part

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#1

  1. I want to achieve a system where you can detect when someone is beside the corner of a part.

  2. I am bad at math and I don’t know how so could you guys explain to me what you would need to do.

    Saved as C__Users_bloxs_Downloads_double jump parkour.rbxl - Roblox Studio 01_06_2021 20_55_01
    Saved as C__Users_bloxs_Downloads_double jump parkour.rbxl - Roblox Studio 01_06_2021 20_55_011920×1080 538 KB

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#3

Why not just check if the player is touching the part?

#4

make a small part which is on the corner of that part and use that

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#5

I’m sorry but what if I have thousands of parts? I don’t want to make a part for every corner. I want the real way the real math to get the parts corner.

#6

I am sorry but I don’t want to. I want to know whethere the player is at the corner not touching the part. its 2 different things :confused:

#7

Surface Area
hmmmm… i wouldent know

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#8

yes I do need to learn math but I am quite horrible at it. If its so easy math could you help out?

#9

Is it even achivalble in a roblox game liek has someoen done it before?

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#10

yes there are people who have done it before like for example in a parkour game. It detects whether someone is on the Ledge or not and makes him hold on and climb

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#11

Are they all going to be blocks? If so all you need to do is take the part sizes, find the part’s position, and find the 8 corners using those sizes. For example, if the bottom left front corner is at 0,0,0 and you know the size in the Z direction is 2, then you can find the top left front corner to be the same X and Y position but 2 studs up on the Z axis. And so on.

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#12

No u need to use vectors like
What you want to find that 3d corner? Let’s find out

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#13

Ooo I see. Know that’s what I’m talking about. Yes all the parts are going to be blocks.

#14

I want to find the ledge which is the top edge of a part.

#15

You can get the corners of the part by doing

local corner = part.CFrame * CFrame.new(part.Size.x/2, part.Size.y/2, part.Size.z/2)

or a shorter way is
local corner = part.CFrame * CFrame.new(part.Size * .5)

There are 8 corners of a cube. Those are:

local offset = part.Size * .5
local corner = part.CFrame * CFrame.new(offset)
local corner2 = part.CFrame * CFrame.new(-offset)

offset = Vector3.new(-offset.x, offset.y, offset.z)
local corner3 = part.CFrame * CFrame.new(offset)
local corner4 = part.CFrame * CFrame.new(-offset)


offset = Vector3.new(offset.x, offset.y, -offset.z)
local corner5 = part.CFrame * CFrame.new(offset)
local corner6 = part.CFrame * CFrame.new(-offset)


offset = Vector3.new(offset.x, -offset.y, offset.z)
local corner7 = part.CFrame * CFrame.new(offset)
local corner8 = part.CFrame * CFrame.new(-offset)

There’s probably better ways of getting corners but this is one atleast.

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#16

The way you would do it is probably the easiest by using region3. Since it is basically impossible to get directly on the edge of a part you can create a region3 where the edge is instead.

The maths is simple and understandable…compared to other things lol One way you can look at is is in 2d

If I have a box that is 4×4 then To region2 for the top right edge I would need to get the Position of the 2d square then 3.5,3.5 in object space to world and 4.5,4.5 in object space to world make a region between that and detct when the player enters the region.

Remember the formula to get the position of the edge of a box is

local P1 = Part.CFrame:PointToWorldSpace(Part.Size.X/2 - 2 ,Part.Size.Y/2- 2,Part.Size.Z/2)-- This is asuming you are looking for the right top Edge of the cube
local P2 = Part.CFrame:PointToWorldSpace(Part.Size.X/2 + 2 ,Part.Size.Y/2 + 2,Part.Size.Z/2) -- The region3 will have a radius of 2

Make a region3 with the points and you just have to check if the player is in the region3

I am using radius even though it is not a circle lol. Hopefully yknow what I mean.

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#17

Would that work if the cube is rotated? I am not sure it would.

#18

yes it works when rotated.
Corner is a cframe though so if you want the position do corner.Position

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#19

awesome man. Thanks so much this was exactly what I was looking for. Well deserved that solution button.

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#20

I made this quick function to help you out.

Usage:
2021-12-22 19-29-56

My Code:

wait(2.5)

local function addCorners(v)
	local newPart1 = Instance.new("Part", v)
	newPart1.CFrame = v.CFrame * CFrame.new(0,v.Size.Y / 2,0)
	newPart1.CFrame = newPart1.CFrame * CFrame.new(v.Size.X / 2, 0,0)
	newPart1.Size = Vector3.new(1, 1,v.Size.Z)
	newPart1.Anchored = true
	local newPart2 = Instance.new("Part", v)
	newPart2.CFrame = v.CFrame * CFrame.new(0,v.Size.Y / 2,0)
	newPart2.CFrame = newPart2.CFrame * CFrame.new(-v.Size.X / 2, 0,0)
	newPart2.Size = Vector3.new(1, 1,v.Size.Z)
	newPart2.Anchored = true
	local newPart3 = Instance.new("Part", v)
	newPart3.CFrame = v.CFrame * CFrame.new(0,v.Size.Y / 2,0)
	newPart3.CFrame = newPart3.CFrame * CFrame.new(0, 0,v.Size.Z / 2)
	newPart3.Size = Vector3.new(v.Size.X, 1,1)
	newPart3.Anchored = true
	local newPart4 = Instance.new("Part", v)
	newPart4.CFrame = v.CFrame * CFrame.new(0,v.Size.Y / 2,0)
	newPart4.CFrame = newPart4.CFrame * CFrame.new(0,0,-v.Size.Z / 2)
	newPart4.Size = Vector3.new(v.Size.X, 1,1)
	newPart4.Anchored = true
end

for _,v in pairs(game.Workspace:WaitForChild("Buildings"):GetChildren()) do
	if v:IsA("Part") then
		addCorners(v)
	end
end

game.Workspace.Buildings.ChildAdded:Connect(function(v)
	addCorners(v)
end)

There are most likely easier ways to do this however this is just a quick method I made for you.

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