Keep Simulation Changes
Press K during Simulate to copy the selected actors' simulated state back to the editor level.
Use the K shortcut to keep simulation changes on the selected actors during Simulate In Editor. When you stop the simulation, those actors keep their simulated transforms and properties.
A very useful shortcut for set dressing ;) Drop a pile of rocks or props with Simulate Physics enabled, let them fall into place, and keep the result.
How do I keep simulation changes?
- Start Simulate with
ALT + S. - Let the physics settle.
- Select the actors you want to keep.
- Press
K, or right-click a selected actor and choose Keep Simulation Changes. - Stop the simulation.
What gets kept?
The command copies the actor’s editable properties, including its transform, from the simulated actor to its counterpart in the editor level. A notification shows which actor was saved and how many properties were copied, and if nothing changed, it reports “No properties were copied”.
Simulating skeletal meshes get an extra prompt. Choose Yes to capture the current pose as a single-frame animation and apply it to the editor actor, with physics simulation turned off. This option is unavailable for Blueprint actors.
Frequently asked questions
Does it work during Play In Editor?
Yes, as long as you can select the actors.
Why weren’t some of my changes kept?
Actors spawned during the simulation have no editor counterpart, so there’s nothing to copy them to. Attachment changes are also left behind.
Can I undo it?
Yes. The copy is recorded as one Keep Simulation Changes transaction in the undo history.
Why did my props move again the next time I played?
They still have Simulate Physics enabled. It’s ideal to turn it off on props after keeping their positions, so they stay where you put them.
Links
Check out the following resources to learn more about the subject.
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