I’m using a weldConstraint to weld items to the player in my game, I set the weldconstraint’s CFrame using SetPrimaryPartCFrame then set up the Part0 and Part1 after, but since the player is moving it causes weird offsets. Any way to code it correctly using WeldConstraints?
The code I am using to attempt to weld it correctly:
It looks like the issue is because WeldConstraints are simulated individually between clients and the server, rather than having their values synced across everything.
In a test server and in-game, there’s some amount of latency, so the character appears in one location on the server while it’s slightly somewhere else on the client. Since the cheese is created on the server, it uses the server’s position of the character – this is why the cheese looks as it should on the server. However, since the cheese’s position is not lined up with where the client thinks the character is, you get odd results like this.
This doesn’t seem like good behavior. I’ll make a feature request for the offset to sync across the server/clients instead of being simulated disjointly. I would recommend using normal Welds in the meantime.
I was experiencing an issue like this with a character model I had put together. The WeldConstraints would be offset outrageously upon creating the character.
For those in a rush, here is a quick and dirty script that can convert WeldConstraints on an already existing model to Welds.
local baseModel = workspace.MODELNAME
local model = baseModel:Clone()
baseModel.Name = baseModel.Name .. "_Old"
local function weldBetween(a, b)
local weld = Instance.new("Weld", a)
weld.C0 = a.CFrame:inverse() * b.CFrame
weld.Part0 = a
weld.Part1 = b
return weld
end
for _,constraint in pairs(model:GetDescendants()) do
if constraint:IsA("WeldConstraint") then
local a = constraint.Part0
local b = constraint.Part1
if a and b then
weldBetween(a, b)
end
constraint:Destroy()
end
end
model.Parent = baseModel.Parent
I’m using WeldConstraints to attach a gun (model) to the player using 3 main parts;
headAnchorPart - this is CFramed to camera.CoordinateFrame
gunAnchorPart - this is used to offset the gun from the headAnchorPart - the centre point for the gun’s handle.
gunHandle - the actual handle of the gun.
This is what it should like - Red being = headAnchor, green = gunAnchor, and pink = handle
The attachments represents the different states of offset of the gun from the camera (holding, running, iron-sights)
Instead of the the headAnchor cframing to the cam’s coordinate frame though - it keeps offseting, as if it is centring on the middle point of all connected parts:
Whether I’m missing something completely or this is a bug - I don’t know but this is very strange.
I expected that the applied cframe be respected, not offset by the connected parts.
For now I’ll try to use legacy welds, but if this could be fixed in the future, that would be awesome - WeldConstraints are way easier to work - besides the odd bug.
This is still an issue 2 years after this being posted. I can’t stress it enough; The offsets caused by latency between the server and its clients when using WeldConstraints is absolutely a bug.
Report it them via #platform-feedback:engine-bugs if you genuinely think it’s a bug. Posting here does nothing good except bump a thread from over a year ago.
Yup, a similar issue still occurs in our game as well.
local Weld = {}
local function manualWeld(partA, partB)
assert(typeof(partA) == "Instance" and partA:IsA("BasePart"), "partA needs to be a Base Part.")
assert(typeof(partB) == "Instance" and partB:IsA("BasePart"), "partB needs to be a Base Part.")
local weld = Instance.new("ManualWeld")
weld.C0 = partA.CFrame:toObjectSpace(partB.CFrame)
weld.Part0 = partA
weld.Part1 = partB
weld.Parent = partA
end
-- Currently does not work on character reset
local function weldTo(partA, partB)
assert(typeof(partA) == "Instance" and partA:IsA("BasePart"), "partA needs to be a Base Part.")
assert(typeof(partB) == "Instance" and partB:IsA("BasePart"), "partB needs to be a Base Part.")
local weld = Instance.new("WeldConstraint")
weld.Part0 = partA
weld.Part1 = partB
weld.Parent = partA
end
function Weld.WeldModel(character, clonedModel, characterModel)
local characterContent = character:GetChildren()
for _, bodyPart in pairs(characterContent) do
local modelPart = clonedModel:FindFirstChild(bodyPart.Name)
if modelPart then
local offsetCFrame = characterModel[bodyPart.Name].CFrame:toObjectSpace(characterModel[clonedModel.Name][modelPart.Name].CFrame)
modelPart.CFrame = bodyPart.CFrame * offsetCFrame
manualWeld(modelPart, bodyPart)
--weldTo(modelPart, bodyPart) -- Does not work on character reset
end
end
clonedModel.Parent = character
end
return Weld
Demonstration of the issue:
WeldConstraint works fine the first time a game character is applied to the player’s character.
But from the second time onwards, there is an offset when using the WeldConstraint, ManualWeld fixes this issue and works fine.
I hope this can be looked into.
EDIT: Added video to demonstrate issue.
EDIT 2: After looking around on the devforum some more, I shouldn’t use WeldConstraints for characters, because those welds are most likely to be used for static offsets only.
