Moving Mouse in Phat Editor while simulating causes unintended reaction

Hi,

I don’t know if this is a bug or a feature. While simulating a Skeletal Mesh in Phat and moving the cursor, without pressing anything inside the viewport, the Physical Simulation reacts to the movement. How can I deactivate this?

I made a video and included the project into a zip file here: dropbox

Edit: I observed this behaviour not only in Phat, placing physical simulated Actors in a level and press simulate you will see the same jittering while moving the mouse (you can obeserve this in my example above too). If you hit play the jitter disappears. Pressing shift-F1 to leave the play-in-viewport mode the jitter returns if you move over buttons in the shelfs.

In order to record animations with physics, I wait some seconds after hitting simulate and record until it stabilizes, then I press play and keep the cursor there. Edit_2: Tooltips of Pause and Play still cause Jitter.

Kind Regards,
Arvid

Seeing a similar issue trying to set up a chain of bodies. Moving mouse in window (without touching anything) causes the chain to jitter and become unstable.

Hi Arvid,

Thank you for the info and the test project. I was able to reproduce this behavior so I have created JIRA UE-52740 and our developers will be investigating further.

-TJ

I want to add that it’s still an issue with UE4.20. Was it fixed in 4.21?

All in all PhaT is not the easiest thing to work with in terms of it’s glitching and instability of physics simulation.

Hi, it is still an issue in 4.21. Epic tagged it as “Won’t Fix” in JIRA. I do not know the reason, I guess we have to live with that, or fix it ourself :slight_smile: - Arvid