WeldConstraints shift parts constantly

I am attempting to make characters in one of my games by welding all of the parts of the model together, but when I am moving a certain part of the character (or not even moving at all, just clicking the arrow) it seems to shift the part to the left, and in some cases the entire model which messes up everything.

I expect the part to only move when I move the part, and if I move it to only move how far I let it go.

This bug seems to happen most of the time, usually when welding multiple parts to a certain base part.


Steps to Reproduce
Open this place and try moving each part around in the model under workspace named “Dummy”. You will see a shift when moving the part. This seems to only happen when the model is rotated.
Place: WeldConstraint File 2.rbxl (55.3 KB)


Video of bug:

The humanoid is around (6111.5, -207, 8189.5) in the video above.
When moving it to (239.497, 90.998, 498.999) it still happens but seems to only shift to the right (not down) and does it less.

I believe the farther away from 0,0,0 it gets worse but it can still happen only 100 studs away from origin.

If this helps to find a solution, it seems that wherever the part is that I move, the Position property does not update under the properties window until I de-select and select the part again. Also when toggling the “Enabled” state of the WeldConstraint, it makes the part shift. Even using the command bar and shifting it slightly it still occurs.


I am on PC Windows 10 Home and this happens in Studio while editing my game. This bug has happened for as long as I remember using them - around a year ago.

12 Likes

I have the same issue, apart from that WeldConstraint sometimes adds odd offset to the part, but only on the player side. They should fix it as soon as possible.

2 Likes

Have you gotten any feedback about this? I have the same issue and I’m using weld constraints to hold together a sword and many of the chars that use it are rendered useless since the sword is a major aspect of their abilities

2 Likes

I tried to tween two islands together by tweening the PrimaryPart’s CFrame. I couldnt do it because of the welds. They kept moving slightly when I attached them.

Edit: It happens to active Weld Constraints, I managed to take a video of it. In the video you can clearly see the part moving slightly after I placed it.

4 Likes

Any updates? I’m having this glitch in a game I’m working on to a pretty extreme degree. I add a handle to a tool and attempt to weld it to the other part inside the tool. When I’ve tried this in the past, welding works just fine, but this time the part will move very far away. I don’t want food items being held and showing up halfway across the map.

Recorded a video with the handle visible, at first, the WeldConstraint isn’t enabled. After enabling, the handle is shifted a huge distance away.robloxapp-20200813-1203196.wmv (3.7 MB)

1 Like

Happens to me as well. I just ended up making a weld module and welding the parts I wanted together instead of using a WeldConstraint.

1 Like

Gave that a shot. While it welds, the handle will always shift to the center of the tool.

I’ve found a workaround, at least for me, where I used the “Create” button in constrains to make the WeldConstraint. This works so long as I position the handle before adding the constraint.

1 Like

I have good news, the issues with WeldConstraints doing stuff like this are (finally) going to be put to rest soon, a fix for this is currently making its way down the pipe.

6 Likes

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