When creating one or more WeldConstraints by running the following code inside the command bar(I found this issue while creating WeldConstraints using more complex code but this simple code also causes the issue to occur), the WeldConstraints disappear (I’m asuming they get deleted/Parented to something that isn’t accessible like “The command bar dimension” ) when selecting the WeldConstraint Tool in the Model-Tab.
I also wanted to add that if I refer to “Welds” I still mean WeldConstraints or the Tools/Settings related to WeldConstraints.
The code is as follows(Changing the order of the instruction(Like e.g. parenting the WeldConstraint after setting Part0 and Part1 instead of beforehand) doesn’t affect the problem):
local Const = Instance.new("WeldConstraint")
Const.Part0 = game:GetService("Workspace").Part
Const.Part1 = game:GetService("Workspace").Part1
Const.Parent = game:GetService("Workspace").Part
This issue occured in a existing game of mine as well as a freshly created game using the “New Experience” button. I already tried running Studio with all plugins temporarily disabled but that didn’t resolve the issue. I also tried putting the Parts into a Folder inside the Workspace as well as putting them directly into the Workspace but this also caused no difference.
The steps of recreating this issue are as follows:
- Create a new game or open an existing one
- Add two Parts into the Workspace(In my case I named them Part and Part1)
- Run the code above inside the command bar(Adjust the paths to the Parts if they are different)
- Go to the Model-Tab
- Select the WeldConstraint-Tool (It should say Weld underneath; pay attention that the Weld-Tool is selected, not the “No Collision”-Tool)
- You can already see that there are no children inside the Parts in the Explorer and will notice that the WeldConstraint created earlier also disappeared if you have Welds enabled in the Studio Visualization Modes
- Either press Esc to exit the Tool or create a Weld between two different Part or the same Parts(It doesn’t matter since the WeldConstraint already got deleted but if you weld it to different Parts it is more noticable that the WeldConstraint was deleted than if you weld the same Parts together again)
I also included a video of me replicating the steps(Sped up to twice the speed because the files would else be to large).
I noticed the issue the first time at around 9 pm CEST on the 31st of August 2025.
My system information is as follows:
CPU: AMD Ryzen 5 5600G with Radeon Graphics
Memory: 32GB
GPU: Radeon RX550/550 Series
The beta features I have enabled are as follows:
- Acoustic Simulation
- Assistant Mesh Generation
- Avatar Joint Upgrade
- Detached Attachments
- Dragger QoL improvements
- Face Capture
- glTF Export
- Haptic Effects
- Improved Constraint Tool
- In-Experience Avatar Auto Setup
- Live Animation Creator
- New Display Size API
- New Studio Camera Controls
- Next Gen Studio Preview
- Preferred Text Size Setting
- Revamped Asset Manager
- Script Sync [Early Preview]
- Texture Generator
- UIDragDetectors
- Video Uploads
I have also included a repro file just in case but I don’t think it’ll be neccessary since this also applies to freshly created games.
Repro File Weld Constraint Issue.rbxl (56.6 KB)
Expected behavior
I expect the WeldConstraint created using the command bar to not disappear but instead stay the way it is like a WeldConstraint created via the Tool in the Model-Tab would.