"Light as if Static" setting does not persist

This has been a problem for a very very long time (since 4.8?) I have a scene with hundreds of static meshes that need to be movable but also lit with Lightmass. Every time I open my project I have to go through and reset the “Light as if static” setting on about half of them before doing another lighting build.

Please see these old posts for details. Why has this not been addressed?

Hello StephaBon,

I would like to know if each of these static meshes marked as ‘Movable’ that you are attempting to integrated into static lighting, have lightmap UVs?

Is this a project you have upgraded from a previous version?

I tested this issue in a blank project and did not get the results you are reporting. Would you mind doing the same with some simple primitives that have lightmap UVs?

Thank you,

Hey . All these objects have pristine and perfect lightmap UVs that we take very seriously. This is a new project that started in 4.11 Preview and all meshes were modeled within the last 2 weeks.

Lighting works perfectly. Everything works fine until the editor is closed. Then a random assortment of objects loses the attribute. I’d be happy to take screenshots or send the whole project over.

I think the best solution would be to provide me with this project so I can confirm what you are reporting. I have tested with a few different project types and all are saving the setting upon re-opening.

Just use the ‘Zip up Project’ option within the File menu and then upload it to a sharable google drive link and share the project with me in your response. If there is content that needs to remain private, you can send the link via a private message.

Thank you,

Private message sent.
Still can’t find a pattern on what objects keep or lose their setting. Seems like about 5% of objects are fine. Everything else resets whenever I close the project. I also just sent the project to another computer via SVN (without closing it), and it was also reset.

Hey StephaBon,

I have been trying to find a good case in which this reproduces. Your project is pretty densely populated with a number of different assets and lights, which increases the difficulty of narrowing down the variable(s) that cause this issue to occur.

I will say, the one thing I have noticed with this issue, is that it directly pertains to the asset containing a unique UV for the materials as well as for the lightmaps. I was able to reproduce the issue in your project, but I cannot really submit the bug report using your entire project. Once I can reproduce in a template project or sample, we can move forward with the reporting process.


Thanks for checking on that and confirming. I felt inspired to check this in the FPS template and was able to reproduce!

Create new FPS template project

Select all static meshes in scene (EditorCubes, Floor, BigWalls, Walls)

Set to Movable

Set to “Light as if Static”

Build Lighting

Close Project (and save)

When I reopened it, sure enough BigWall2 did not have the setting saved. I thought maybe I missed that one, so I rebuilt lighting and reclosed. Then everything was saved right.

Closed and opened. Everything was okay.
Closed and opened. Everything was okay.
Closed and opened. BigWall2 not saved! When selecting all the meshes, the Light as if Static setting shows mixed results.


Hey StephaBon,

So I was unable to get this issue to occur on my end, but another teammate of mine was able to do so. I know you narrowed it down to the template project, but unfortunately it is only occurring for a single asset, and the repro case is not super reliable. Entering a bug for this is going to need a reproduction case in a blank project with only a few assets in which it occurs reliably. I appreciate your patience while we work through this issue.


It’s definitely a slippery problem, but I hope you guys aren’t giving up. I just did some testing of my own by opening and closing projects about 90 times (dear god why) and came across an interesting pattern.

First, make a blank project, clear all the editor and game startup maps in the settings, set the default starter platform to Movable, check the “Light as if Static” checkbox (LAIS), build lighting, save the map and close the project. I then proceeded to open and close the project a million times, making sure to save the platform with the LAIS setting if it disappeared.

LAIS persisted 6 times out of 15.

I then set this map to be the startup default for editor and game.

LAIS persisted 1 time out of 15.

I cleared the default maps again.

LAIS persisted 8 times out of 15.

Reset the map to be opened by default.

LAIS persisted 0 times out of 15.

Cleared the default startup maps.

LAIS persisted 7 times out of 15.

It’s still not a concrete and clear issue, but to me this shows some evidence that the startup settings are affecting the chances of failure. Maybe there is a simple logic error in the level loading and level saving scripts?? Just grasping for an explanation since this bug has been around for close to a year now. I want to encourage you guys to dig into it. Go team! You’re the best!

Thank you for remaining patient and taking the time to test this issue thoroughly. I took your steps and repro instructions and created a bug report for this issue (UE-30080). Once the issue has been fixed, it will be integrated into an upcoming full engine release or hotfix. Again, we appreciate you following through with this report and let me know if you have further questions or need additional assistance.

Thank you,

This problem still persist. I have blueprint with simple box that is door glass object, with lighmap UV’s of course.
It is movable, project is not upgraded from old version.