Weld Constraint behaves differently on Server compared to Client

Bug Reports Engine Bugs
#1

I would like the weld constraint to behave in a normal manner (it should not displace parts as shown in the video).

For some reason, the weld constraint seems to be behaving differently on the client compared to the server. From a server-side point of view, it looks fine. But when I change to the client’s view, things get a little displaced (as shown in the video). All parts that are visible in the video are owned by the server (network-wise).

The following video displays the problem (watch the propeller).

I have not tried any possible solutions so far yet, because I am still confused about the origin of this problem.

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#2

Hmm, not sure I’m seeing the same effect you are in the video. I just see camera movement in the video. How is the propeller being displaced?

#3

If you watch closely (from the client’s point of view), you can see that the furthest propeller blade has a slight offset to the left side. Once I switch to the server’s point of view, you can see that the propeller blades seem to be placed correctly.

I adjusted the speed of the video. I hope this helps.

#4

That’s opposite of what you originally posted.

For some reason, the weld constraint seems to be behaving differently on the client compared to the server. From a server-side point of view, it looks fine. But when I change to the client’s view, things get a little displaced (as shown in the video)

Maybe you could post pics side by side and point to the issue. Or maybe someone else can jump in here and say what they are seeing.

#5

I made a small error. My original post contains the right information and I edited my previous reply.

1 Like
#6

Hi!

I’m also experiencing this, and I know another accelerator team has been experiencing this too. Was wondering if anyone has found a work-around.

You can reproduce this by CFraming/moving a model after welding it, or by welding stuff very quickly after moving/resizing it. Might have to do with replication order.

In any event, this is very annoying. I have a consistent repro if you need it.

Does anyone have any work arounds for this?

Edit: I think this is another example of it? Not sure. Odd Weld Constraint Behavior - #4 by IraTenebrarum

2 Likes
#7

Hi, that’s my post you just linked!
My issues were caused by setting the Direction Vectors (Right, Up, Look) incorrectly and not realizing it.
I don’t understand why the engine allows us to set them improperly, but you may have to rewrite your code that handles setting the CFrames of parts.
Hope this helps!

#8

In this case, I’m just cloning the model over, and it appears different on the server vs. the client.

image
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#9

Oh geeze, just realized my bug report got merged into scripting support.

This is DEFINITELY a bug.

Edit: I’ve moved this to engine bugs

#10

I’m also having the same issue. I tried weld constraints, manual welds, perfection weld (I believe most people know this weld script?)without success. I also tried storing part positions before creating weld constraints and unanchoring parts, then move parts to stored positions, but this doesn’t work either.

#11

I have issues like this in my game aswell.
https://www.roblox.com/games/166986752/Plane-Crazy?refPageId=cb1c53fd-fb46-459f-b10e-b75161690c47#!/about

I did notice the effect can get get worse depending on the server.
Whenever the server is lagging, the offset becomes larger.

I think it has to do something with the network delay.

#12

Could you share that particular model and the code that activates the winglets? That looks like it might be a good candidate to reproduce this.

EDIT: The physics team has a solid repro for this issue now, so progress should come soon.

7 Likes
#13

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