Could not create collision group?

Help and Feedback Scripting Support
#1

So I had this bug recently pop up in code that I haven’t touched for several weeks.
The code errors for no reason when I try to create a collision group.

This module function’s purpose is to remove collisions between player characters. Does anyone know why exactly my code breaks when I simply try to create a collision group? The error I am given tells me no useful information.

module.ToggleCollisions = function(bool)
	local physics = game:GetService("PhysicsService")
	if not bool then
		physics:CreateCollisionGroup("ActivePlayerCollisons") --error here
		physics:CollisionGroupSetCollidable("ActivePlayerCollisons", "ActivePlayerCollisons", false)
		local activePlayers = workspace.GameStuff.ActivePlayers:GetChildren()
		for i,v in pairs(activePlayers) do
			local player = game.Players:FindFirstChild(v.Name)
			if player then
				local char = player.Character
				if char then
					--recurse char body parts and hats
					module.PartsList = {}
					local NewParts = module.RecurseParts(char)
					for y, part in pairs(NewParts) do
						physics:SetPartCollisionGroup(part, "ActivePlayerCollisons")
					end
				end
			end
		end
	else
		physics:RemoveCollisionGroup("ActivePlayerCollisons")
	end
end

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image1414×191 113 KB

3 Likes
#2

Means the collision group already exists.

game:GetService("PhysicsService"):CreateCollisionGroup("TEST")
game:GetService("PhysicsService"):CreateCollisionGroup("TEST")

Will cause the same issue

Unfortunately there aren’t any ways to check if a collision group exists by its name (Without erroring when it doesn’t exist) other than iterating over all collision groups with GetCollisionGroups

function collisionGroupExists(name)
    for _,v in pairs(game:GetService("PhysicsService"):GetCollisionGroups()) do
        if v.name == name then
            return true
       end
    end
    return false
end

You could always catch it with pcall but errors are prone to change

1 Like
#3

Fret not, for I have the solution

#4

Now try it with a name that doesn’t exist and get this Collision group not found.

3 Likes
#5

Nice, that definitely shouldn’t be happening.

1 Like
#6

Thank you for the help guys.

This error should definitely be better explained in the output.

1 Like
#7

Hey Ripull, do you know if this code is executing from a LocalScript thread on the client or a server-side Script?

That’s the one thing that’s not clear here. I don’t believe it works on the client right now, which is something I have in my queue to fix (for setting at least, not creating).

1 Like
#8

No no, this was server side.

Is it possible to change the error I received in the original post to “Could not create Collision Group, Collision group already exists” so that people encounter this mistake in future don’t get stuck on this like I did?

1 Like
#9

Oh great, easy. So checking if the group exists first fixed it? I’ll fix that error message then.

#10

Yes, this appears to be the case, my game has been running with this fix for 24 hours now and no more reports of issues.

#11

Problem is that checking if the group exists and it doesnt will also error so youre gonna error either way.
Ive submitted a bug for this.

1 Like
#12

Yep, also an issue. @ContextLost desired behavior is:

  • Calling CreateCollisionGroup for an existing group will just return the existing group
  • Calling GetCollisionGroupId/Name when the collision group doesn’t exist returns nil instead of throwing an error (this is Lua – not a lower level language like C++)
1 Like
#13

Not sure if I’m experiencing the same error for a different reason, but anyone know if this has been fixed? I’ve got this:

image
Been having the error for a few months now, and since its not a very important part of a game I don’t develop much anymore I haven’t got round to fixing it. image

5 Likes