✓ ANSWER ACCEPTED

How do I check if an instance's parent exists?

Asked Mar 19, 2020450 views2 answers

Hello! I have been trying to make a raycasting gun that checks if it hit a character or the character's held tools. So far I could not find anything about this.

My code:

if hit then
		if hit.Parent:FindFirstChild("Humanoid") or hit.Parent.Parent:FindFirstChild("Humanoid") or hit.Parent.Parent.Parent:FindFirstChild("Humanoid") then
			if hit.Parent.Humanoid.Health > 0 then
				hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - 10
			end
		end
	end

Why am I trying to see if it hit any of a character's tools?

I want the player to be able to shoot the other player ignoring if the slight part of another gun is blocking it.

How my Tool looks Image/Picture

Error(s)/Stacktrace

12:25:06.349 - ServerScriptService.ServerGun:21: attempt to index field 'Parent' (a nil value)
12:25:06.350 - Stack Begin
12:25:06.350 - Script 'ServerScriptService.ServerGun', Line 21
12:25:06.350 - Stack End

Answer/What I did to solve it: https://pastebin.com/raw/cd2RC2gy

AnonymousMar 19, 2020Edited Mar 19, 2020

2 answers

✓ Accepted answer

try checking if it isnt nil (nil = nothing, nothingness.) check if something isnt nil by the code below:

if part then
	print("it exists!")
end

alternatively:

if part ~= nil then
	print("it exists (too)!")
end

if hit then
	if hit.Parent then
		local hum = hit.Parent:FindFirstChild("Humanoid") or hit.Parent.Parent:FindFirstChild("Humanoid")  or hit.Parent.Parent.Parent:FindFirstChild("Humanoid") 
	        if hum then
	            if hum.Health > 0 then
	                hum.Health = hum.Health - 10
	            end
		end
	end
end

hope that helped

AnonymousMar 19, 2020Edited Mar 19, 2020Permalink

4 comments

I tried adding ~= nil to all of the 'or' checks, it did not work.

AnonymousMar 19, 2020#

no, the thing is, there isnt a parent for the instance hit

AnonymousMar 19, 2020#

Yeah, that is the problem, if there is no instance it will just error thus creating a massive amount of errors in a full game. Although, I did try something similar and it worked. You apparently cannot try to match FindFirstChild() with nil, so I got around that. I will mark your question as an answer as it partially worked after I extended it, thank you for the solution!

AnonymousMar 19, 2020#

For anyone looking for what I did, here you go: https://pastebin.com/raw/cd2RC2gy

AnonymousMar 19, 2020#

Your code checks if the part hit is correct, but gets the wrong humanoid.

if (hit) then
	local humanoid = hit.Parent:FindFirstChildOfClass("Humanoid") or hit.Parent.Parent:FindFirstChildOfClass("Humanoid")
	if (humanoid) then
		hit.Parent.Humanoid:TakeDamage(10)
		--we don't know if it's the second parent or not
		--which means it'll error if it hits a hat or tool
	end
end

Correction

if (hit) then
	local humanoid = hit.Parent:FindFirstChildOfClass("Humanoid") or hit.Parent.Parent:FindFirstChildOfClass("Humanoid")
	if (humanoid) and (humanoid.Health > 0) then
		humanoid:TakeDamage(10)
		--we know for sure the humanoid exists
		--which means errors aren't possible unless
		--hit's parent is nil
	end
end

As you can see, the var humanoid checks if the parent of the part is the character and looks for the humanoid. The or is used to check the second parent (incase the raycast hits tools or hats).

Note: Humanoid:TakeDamage() will not damage the humanoid if they have a forcefield. Subtracting the health will damage unless their health is inf.

AnonymousMar 19, 2020Permalink

1 comment

Thanks for providing this answer!

AnonymousMar 22, 2020#

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