PhysicsSimulation causing immense consistent lag spikes

Bug Reports Engine Bugs
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I am completely unsure of how to reproduce this bug, but something with the PhysicsSimulation (specifically StepContact) is causing immense amounts of lag in my studio sessions with no apparent leads on to what is going on.

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I have disabled all of my scripts, there are barely any physical moving parts in the game, all models that are to be anchored are anchored. I’ve ran several scripts in the command bar during test sessions to attempt problem fixing but to no luck whatsoever. Anchoring all my parts, deleting all of my game slowly to attempt debugs with absolutely no leads.


All of the parts that are supposed to be moving are frozen and twitching because the server is running so badly.

Expected behavior

Well, I’d expect the game to run normally. Nothing was added to the game from before it started, it just started. Reverting the place file, downloading older place files from weeks ago and publishing to different places yields no results.

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Closing this out as “Won’t fix” as the main issue here is the generation of an extremely high number of contacts (~50,000 contact pairs). To avoid generating this many contacts, you can consider anchoring some of these parts until a player is in proximity. Additionally, for mesh parts, you can lower the collision fidelity to reduce the number of contacts. Longer term, we are working on improvements that should make these systems more automatic and avoid these kinds of slow downs when we have a large number of unanchored parts and contacts.