Performance drop on consecutive physics simulation

Simulating physics for Primitive components causes severe performance drop if simulation is paused, object is moved (using set location) and simulation is restarted. The performance drop accumulates each time the simulation is resumed.

Steps to Reproduce:

  1. Spawn an actor with primitive component as root (typically a static mesh).

  2. Weld attach a few other primitive components to the root primitive component

  3. Setup logic so that a key press toggles simulate physics option for the root component

  4. Now enable simulation then stop it , start it and then again stop it, very soon there is a huge performance drop that increases with each time simulate physics is enabled

Hi Commander Shepard,

I was able to reproduce this, so I’ve created JIRA UE-22905 in our tracking system. Our developers will be investigating the issue further and we may post back here with additional questions or comments.

As for a workaround, the issue doesn’t seem to effect Standalone Game.



Would it be possible to look at the stats to see which one is getting larger and causing the slowdown?

Any updates on this?

Hi Commander,

Not at the moment. I did some further testing after James posted below and provided the devs with additional stat info. It is queued up in our tracking system to be investigated.