[4.9.2] Modifiying point light source radius/length corrupts level lighting


  • Place point light in level
  • Change source radius to 10, source length to 120 (values don’t matter)
  • Build lighting
  • Save map
  • Reload map

Now delete the light (or hide them) and rebuild. Meshes are still lit. It seems not possible to make the level completely dark again. Reloading the level doesn’t help.

Hi ,

Using your steps listed I’m not able to see the same results in 4.10. This may have been an issue with 4.9, but I do not recall anything being reported that this was the case.

The closest issue I can think of was a Tone Mapper issue with 4.8 that prevented a scene from being rendered as fully black, but that was a post process issue and not a lighting issue. That one was fixed in 4.9 though.

For my test, that you didn’t specify in your repro steps, I used a blank scene and added my own static mesh and light. I didn’t use any default or previously setup scenes. If you did that, make sure that the Environment Color is set to Black in your World Settings panel otherwise you’ll never get a fully black scene.

If you’re still having the issue, try 4.10 and confirm there and update any steps as needed.

Thank you!

Hi ,

many thanks. I could work around it by recreating the level manually. The room was relatively small (4x4 m) and all walls where white. So it seems that there was a massive light boost by indirect illumination after baking which caused the original problem. The strange thing was that the scene stayed illuminated after deleting all light actors from the scene and rebuilding.

Will convert to 4.10 soon, thank you.

If you’re using static lighting that would make sense since just removing the light will not remove any of the baked lighting. Even still any objects that get moved, for instance, a single wall, would be lit by the Volume Light Samples (Show > Visualize > Volume Light Samples) until lighting was rebuilt. You may just need to rebuild the lighting after removing the light to adjust the VLS (Indirect Lighting Cache) to be a proper value.