How do you visualize a raycast as a part?

[rek_kie (Ike)]

So I’m doing raycasting and understand it, but how do you make a part to visualize the raycast? Also please explain why each part is which so I get a better understanding.

[sjr04 (uep)]

How do I visualize a ray?

OP likely wants to see the ray while testing the project. Rays can come in different origins and directions. @OP you can create a very thin part, position it at the origin of the ray. Have it look at the position, then offset it, because if you just position it at the origin of the ray it will be in the middle. local r = Ray.new(origin, direction) local _, position = workspace:FindPartOnRay(r) local distance = (origin - position).Magnitude local p = Instance.new("Part") p.Anchored = true p.Can…

[ExcessEnergy]

Here is a developer hub article on basic raycasting, that might help you out!

https://developer.roblox.com/en-us/articles/Raycasting

[rek_kie (Ike)]

This is basically perfect but can you explain this part (especially the -distance/2):

p.CFrame = lookAt(position, origin)*CFrame.new(0, 0, -distance/2) 

[sjr04 (uep)]

It is explained there.

Basically, without that offset, the part would be in the middle. You want its back face to be at the origin.

The part would be positioned right where the origin is.

Now, that post was using the old raycasting API. I suggest you use the new one now.

-- for more info on these, check out:
-- https://developer.roblox.com/en-us/api-reference/function/WorldRoot/Raycast
-- https://developer.roblox.com/en-us/api-reference/datatype/RaycastParams
local result = workspace:Raycast(origin, direction, params)

if result then
    local distance = (origin - result.Position).Magnitude
    local p = Instance.new("Part")
    p.Anchored = true
    p.CanCollide = false
    p.Size = Vector3.new(0.1, 0.1, distance)
    p.CFrame = CFrame.lookAt(origin, position)*CFrame.new(0, 0, -distance/2)
end

I will update the post I linked to use the new one as well.

[rek_kie (Ike)]

OH wait I get it now.

It gets positioned to the middle (like everything that gets positioned via script) which means you only need half of the part to be offset for it to be completely in front (so divide its length by 2), and then the negative moves it forwards instead of backwards like positive integers would on the Z axis. Please correct me if I’m wrong

And then I’m good with CFrames so I understand the lookAt part the only thing I didnt understand was the -distance/2, it looked way more complicated than it actually was

Alright, thanks! And I’ve already learned the new Raycasting API

[sjr04 (uep)]

@rek_kie

you only need half of the part to be offset for it to be completely in front (so divide its length by 2), and then the negative moves it forwards instead of backwards like positive integers would on the Z axis. Please correct me if I’m wrong

Correct! I was going to show another example for if there was still some confusion. You indeed only need “half of the part”!

[deadwalker601 (Lxtte)]

@sjr04

position

Where are you getting position from?

[Beastcraft_Gaming (Beastcraft)]

If you mean RaycastResult.Position then it is a property of raycastresult which is basically is a vector value which shows where the ray got intersected.

[Le_grandcreateur (Tigris)]

Something i did was create an anchored an dinvisible part , and then created two attachement, one inside the new part and the other in the base of the raycast. Every now and then the part.position = raycastResult.Position