Weld incorrectly snaps Part1 to Part0, leaves behind it's geometry

[Partcline (Ricolantern)]

Hi!

By inserting a Weld into a part, and setting Part0 to a different part and Part1 to the part the weld is in,
the weld will automatically snap Part1 to Part0’s centre.
(In this case, Part0 is Right Arm, and Part1 is the cube)
If you do this while Part1 is Anchored, it won’t snap at all. Which I assume is intended.
However, this is not the issue.
If you then proceed to unanchor the part, the gifs below show what happens.

Weld snaps Part1 to Part0's centre

Moving the part will restore Part1's geometry

For some reason, Part1’s geometry will be left behind.

I have no idea if this happens to other people as well.
Please let me know if it doesn’t!

Thank you for reading.

[ContextLost]

@Partcline

If you do this while Part1 is Anchored, it won’t snap at all. Which I assume is intended.

I don’t like this behavior personally, but it is working as intended. Welds do not affect anchored (or indirectly anchored) parts.

@Partcline

If you then proceed to unanchor the part, the gifs below show what happens.

Classic. This is a bug where the physics engine moves the part but doesn’t tell the renderer that it moved. The second you do something that notifies the renderer that the part moved it fixes itself.

I’ll try to fix this soon. Thanks!

[ScriptOn (Genya)]

Wohoo! Had this issue for a while. Can’t wait to see it fixed.

[ContextLost]

Submitting a fix for this. Should be fixed in a week or two.

[ContextLost]

Enabled. Should be fixed now.

[ContextLost]

That’s probably from this:

NOT Changing the rules for eliminating duplicated Welds and other rigid joints (yet)

Update 2: We just DISABLED this change! We disabled this change at 4:47 PST (September 7th). I found some issues with how it played with replication. It was possible for welds to be added seemingly out of order causing the client to remove the wrong weld before applying the removal of the old weld from the server. The client would up with no weld where the server still had one. This is the kind of terrible desyncronization we were trying to reduce with this change in the first place. This was …

Check your tool’s scripts. When I see this it’s usually caused by multiple weld scripts stepping on each other. Removing all by one of them usually fixes it.