Raycasting =>-----<=>

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#1

My question is:
Can you redirect a ray once it’s created
like say

local ray = Ray.new(blahblah.Position, blahblah.Cframe.LookVector)
--and then change the rotation of blahblah and say again something like
ray.Direction = blahblah.Cframe.LookVector

please tell me if this is possible which i suspect it’s not,
Tem

#2

Not through API, you’d just recall the raycast by getting the end position result then get the vector difference of the end result and origin (blahblah.Position - blahblah.Position, order matters so if this isn’t correct, it’ll just be the reverse)

That difference between the origin and end result of the raycast is a vector that you can use as the direction to go back from, or you could probably get a negative version of your original direction (-blahblah.CFrame.LookVector).

I also recommend using the new raycast API that replaces the need for Ray.new, you can still however use Ray.new for the origin and direction if needed (yourRay.Origin or yourRay.Direction).

#3

so you basically say that I should use workspace:Raycast() ?

#4

Yep, you don’t even have to include a RayParams but you can use the RayParams API if you need, it is a little neater in my opinion than filling out arguments for :FindPartOnRayWithWhitelist() even if a little lengthier.

#5

but my question is:
once the ray iis already created can you modify it’s direction?

#6

If you didn’t raycast yet, you can modify the direction to make a new ray. If you mean to change it during raycast or after raycast, the Ray object, yes, but then you’d still have the same origin. You might as well create a new ray at that point. There is no reason to modify the direction if you’re hoping to reflect the ray back.

Here’s code I created on the fly that might represent what you want:

local function raycastThenGetResultBack(origin, direction)
	local firstRaycast = workspace:Raycast(origin, direction)
	
	local position
	if not firstRaycast then
		position = origin + direction -- no instance was found, thus complete the result for ourselves
	else
		position = firstRaycast.Position
	end
	
	-- instead of -direction, you could also do (origin - position) or (position - origin) whichever is correct
	
	local returnRaycast = workspace:Raycast(position, -direction)
	return returnRaycast
end
#7

i am currently making a sword and when it hits it creates a ray that checks if it crosses with another sword but the issue is server performance. with so many rays that are created with the sword moving around i think it’s easier for a ray to change direction than creating 7mil rays that do the same thing. I’m just saying

#8

I believe the less rays you use the higher the performance, direction changing just means making a new ray regardless anyways. The lengths of the ray also matter on performance IIRC.

#9

weeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
and sad in the same time lol

#10

The answer to this is no. Rays are immutable (fancy language that just means that it doesn’t ever change. A mutable object can change). Roblox data types (like Ray or Vector3) are immutable. So if you want a value inside of them to change, you need to create a new one.

This is OK and won’t actually cause any performance problems. A Ray object itself only contains some vector information, but doesn’t perform a raycast operation. The actual raycasting itself is much more costly.

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