Getting a part's face from Raycasting?

[Grayuu]

I want to get the face of the part the player is facing with a raycast if that’s possible. I’m trying to make a ledge climbing system where the player would jump and climb edges.

I have heard about face normal with raycasting but don’t know how I could use that to help me get the actual face(to then get the edges)

Here is the code I have right now

Remotes.TestFunction.OnClientInvoke = function(part,normal)
				print("[PLAYER IS CLIMBING]")
				warn(part)
				local topSurface = part.CFrame * CFrame.new(0,(part.Size.Y/2),0) -- gets the top face of the part

				local edges = {} -- table for storing corners position and how far the edge is from the player

				-- corners positions
				local leftEdge1 = topSurface * CFrame.new((part.Size.X/-2),(part.Size.Y/2),(part.Size.Z/-2))
				local leftEdge2 = topSurface * CFrame.new((part.Size.X/-2),(part.Size.Y/2),(part.Size.Z/2))
				local rightEdge1 = topSurface * CFrame.new((part.Size.X/2),(part.Size.Y/2),(part.Size.Z/-2))
				local rightEdge2 = topSurface * CFrame.new((part.Size.X/2),(part.Size.Y/2),(part.Size.Z/2))

				-- distance between corner and player
				local distanceFromleftEdge1 = (leftEdge1.Position - self.Char.HumanoidRootPart.CFrame.Position).Magnitude
				local distanceFromleftEdge2 = (leftEdge2.Position - self.Char.HumanoidRootPart.CFrame.Position).Magnitude
				local distanceFromrightEdge1 = (rightEdge1.Position - self.Char.HumanoidRootPart.CFrame.Position).Magnitude
				local distanceFromrightEdge2 = (rightEdge2.Position - self.Char.HumanoidRootPart.CFrame.Position).Magnitude

				edges[1] = {distanceFromleftEdge1,leftEdge1}
				edges[2] = {distanceFromleftEdge2,leftEdge2}
				edges[3] = {distanceFromrightEdge1,rightEdge1}
				edges[4] = {distanceFromrightEdge2,rightEdge2}

				print(edges)

				table.sort(edges, function(a,b) -- sort by distance. smallest first and biggest last.
					return a[1] < b[1]
				end)

				local edge1 = edges[1]
				local edge2 = edges[2]


				local distanceBettweenCorners = (edge2[2].Position - edge1[2].Position).Magnitude -- making the edge from two corners

				local inBettween = edge1[2]:Lerp(edge2[2], (edge1[1]/distanceBettweenCorners)) -- getting the player distance and putting the player on the edge

				self.Char.PrimaryPart.CFrame = inBettween -- putting the player on the edge
			end

I’m trying to figure out how to get the exact face of a part the player is facing. Any assistance would be greatly appreciated.

[AceKiron (Ace)]

@Grayuu

I have heard about face normal with raycasting but don’t know how I could use that to help me get the actual face(to then get the edges)

I don’t know much about raycasting, but assuming the part is a block then all 6 faces have their own normal, can’t you just map those normals to faces?

[Grayuu]

I don’t really know how you would do that, would you mind explaining it to me?

[Velliaan]

Explanation of Surface Normal?

The surface normal is a vector, which can be imagined as a description of an arrow in 3D space. In the example given by @jody7777, the arrow is a representation of the vector that is perpendicular (aka normal aka at a 90 degree angle to) the surface at that point. [image] A Vector3 is described as such because it is a vector with 3 components, normally (x, y, z). Now let’s say that the length of the arrow in the above image is 5 units. It is shown to be pointing straight up, in the positive-…

How do you find the side of a part using raycasting?

This is answering the literal title of your post. IT’S MATH TIME! Part of what is returned by a raycasting operation is a normal vector, which is a directional unit vector that faces straight out of whatever face was hit by the raycast. If you simply want to find the side of the part we hit, we can compare the normal vector we hit to the vectors that make up the face normals of the part and return the face for the given side. This leaves us a question: how would we compare two vectors to see …

Getting the corners of a face is a bit more messy since you would need to know which Axis to use maths on, i’m lazy so i don’t know any easy way but i would just code 6 different axis calculations to get the corner of any face.

this is the image i always refer to whenever i need to get the corners of a basepart.

https://images-ext-2.discordapp.net/external/2GsFJHd-N6zdLu0BdOWjj4B7KZBhhIQ3TtO0vyE4JIo/%3Fwidth%3D1009%26height%3D676/https/media.discordapp.net/attachments/932657144191414303/941875705925476402/6b6f081efba33170e35eb80346909228.png

EDIT:
don’t exactly understand the intention of the OPs code, from what it seems you want it so the player can only climb the corners of an instance

[kalabgs (FartFella)]

local function GetEnumNormalFromRay(ray :RaycastResult)	
	local part = ray.Instance
	local Position = ray.Position	

	local Normal = {
		[1] = {Position = part.CFrame * CFrame.new(0,0,-part.Size.Z/2),EnumNormal = Enum.NormalId.Front},
		[2] = {Position = part.CFrame * CFrame.new(0,part.Size.Y/2,0),EnumNormal = Enum.NormalId.Back},
		[3] = {Position = part.CFrame * CFrame.new(0,part.Size.Y/2,0),EnumNormal = Enum.NormalId.Top},
		[4] = {Position = part.CFrame * CFrame.new(0,-part.Size.Y/2,0),EnumNormal = Enum.NormalId.Bottom},
		[5] = {Position = part.CFrame * CFrame.new(part.Size.X/2,0,0),EnumNormal = Enum.NormalId.Right},
		[6] = {Position = part.CFrame * CFrame.new(-part.Size.X/2,0,0),EnumNormal = Enum.NormalId.Left},
	}		

	local Closest = Normal[1]

	for _,Side in pairs(Normal) do
		Side.Position = Side.Position.Position
		local lookForward = Vector3.fromNormalId(Side.EnumNormal)
		local lookToPoint = (Side.Position - Position).unit

		local angle = math.deg(math.acos(math.clamp(lookForward:Dot(lookToPoint), -1, 1)))
		
		if (Side.Position - Position).magnitude < (Closest.Position - Position).magnitude then
			if angle < 90 then
				Closest = Side
			end
		end
	end

	return Closest.EnumNormal
end

local ray = workspace:Raycast(Vector3.new(1,10,0),Vector3.new(0,-15,0))

print(GetEnumNormalFromRay(ray))