UE 5.3 "Simulate Physics" don't work properly

Hi, I have a problem with version 5.3
if I have 2 stacked actors that I can take and I take the one below the one above remains suspended as if the “simultae physics” was deactivated but it is not. (if you hit them with the player they fall normally)
This does not happen in version 5.2.1 (as in the video) using the same project.
Is this a bug or is there a new setting that I’m not aware of?

Thank you for the time you want to dedicate to me.

I’ll try to make you understand better, this is what’s happening to me since version 5.3

Yes this is a bug - it will be fixed for the next 5.3 patch, or if it’s holding you up you might be able to integrate this change from UE5-Main: Chaos · EpicGames/UnrealEngine@fbbe389 (github.com)

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Hi Chris, thanks so much for the reply, I will definitely wait for the fix patch… thanks again and good work :wink:

Bad news though - it won’t make the 5.3.1 patch because the deadline was a couple weeks ago. It’ll be in 5.3.2 now :frowning:

Patience is the virtue of the strong! … in the meantime I found another problem… if in the viewport you change from perspective to orthographic view the engine always crashes.

no improvements in 5.3.2 either… what’s happening?

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Hi Chris, I would just like to know if you are working on the problem or do I have to give up that kind of physics in my project. Thank you for your interest.

A potential work around could be to disable collision on the removed item before you actually remove it. You could also restart the phys sim on the actor above when the one below is removed.

I’ll poke around and see if I can get a good result.

Fresh install of 5.3.2, ThirdPerson sample project.

Created an Actor (BP_PhysicsItem), static mesh as Root.
Set Simulate Physics true
Collision (Physics Actor), Generates Hits

In the Character class I did a simple line trace from camera, hit actor : cast to BP_PhysicsItem → Destroy actor.

Works fine. Stacked physics actor, physics actors that fall and stack. All work fine when you destroy the actor beneath it.

Works fine if I teleport the hit actor to a new location.


Only question that remains for me is… Is this Multiplayer? Are the items Server spawned and replicated? Are the removals done via Server, not local client.

If they are replicated actors and you destroy/remove them locally then it’s working as it should. Servers version still exists, thus the top one will not react.

Removals/Destroys have to happen on the server (authority).

Hi, I do not understand what you mean.

Thanks for the reply.

  1. This isn’t multiplayer
  2. it always worked normally before installing 5.3
  3. I understand that it works for you and I believe it but not for me… and I don’t understand how Chris called it a BUG

I’ll try testing on new layers or try importing everything into a new project.

I’d start with the same test that I did. easy trace to a simple physics actor.

Ok thanks, actually now in 5.3.2 it works in a new level, I just have to re-import everything.
When I tried the same operation with 5.3.1 I had no result and so I imagined that that wasn’t part of the problem too.
Thanks for your support.

:+1:

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