Unanchored Objects Falling Through Parts

I have begun receiving reports from multiple users of physics objects falling through static parts. All of these parts have collision, yet they fall through them as if they don’t. This is incredibly game breaking as our game is heavily physics based. One user reported being able to walk through parts entirely, as if they had no collision at all. I do not have reproducible steps for this to happen. My presumption is that it happens in lag intensive servers.

Our physics mode is set to Fixed.

Game Link: [15M] Oaklands 🌳 - Roblox

Images from a user:



Expected behavior

Unanchored objects should not fall through anchored parts with collision.

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For these reports, what is the earliest report? What OS are they on? Thanks!

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Earliest report was about ~5 hours ago. All reports I have received are Windows (10/11) users. Our network ownership for objects is on the server aside from when a player is dragging an object.

I’ve seen it happen in games before and never thought of it.

I don’t know a fix, but it seems @APandaPoet will already file a report.

Have you received more of these reports since then or additional reproduction steps?
We’re actively looking into it on our side, but at the moment we don’t see any updates which can be the source for such bugs. Any additional information will be highly appreciated.

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So far I haven’t received any other reports from players. I’m not really sure why this happened. It’s impossible for our in-game items to have their collision disabled, and we don’t do anything to allow players to walk through walls.

It seems to be a one-off situation, but with multiple people.

Edit:

I spoke with one of the users impacted by this. Apparently another user in their server had purchased dozens of vehicles and placed their spawn pads down, spawning in the vehicles.

I think there is a possibility that having this many assemblies could have been what resulted in the physics breaking entirely. I can proactively add a limit to vehicle assemblies per player, which I will now because of this, but I am worried that this could happen again with other objects. I do not know if this is “intended” behavior or not.

I will try to create a repro file knowing this information.

Repro file would be extremely useful, thanks! It isn’t an intended behavior, so anything to help track this issue will help.

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Were the part recently created when experiencing the bug?

Personally I’ve been having that issue in Studio when I create a new part, but if I wait a while it doesn’t fall through other parts.

Do you know if objects fall through and continue to fall or if they just hang in the air?
We try to understand if this is more of networking or collision issue

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I am being told from a user that they kept falling until they hit the destruction void and disappeared.

I do not think it can be a networking issue because network ownership is never given to the client (unless the user drags the items), and the items were gone on rejoin as they left the property from falling, resulting in them not being saved.

Do you still encounter this issue? We think that it might be caused by an unrelated change which was reverted.

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I have not experienced this issue in a while, I do not think it is happening anymore.