Lighting is reflecting off water through a complete enclosure

I’m working on an outdoor scene and having trouble with the water from the ‘water planes’ resource.

I recreated the issue in a simple test :

-build a deep-sided rectangular reservoir with all four sides and bottom overlapping so there are no cracks. Add a water plane just above the bottom and outside of the enclosure a direction light shining slightly upward from the horizontal; The water looks fine from the top.

  • Now rotate the light downward by one or two degrees and this completely contained water will begin reflecting it quite brilliantly.

I have read Exterior lighting affects interior water plane - World Creation - Unreal Engine Forums and many others, but unfortunately the light that my water scene is reflecting is the sunlight so I can’t make it static or stationary.

I’d really appreciate any help you could offer on this.

Hello Eredin,

In order for me to assist you, would you please provide a screenshot of your light actors as well as your scene set up? I do appreciate the explanation of your scene and the steps you are taking to get the outcome, but I will need a bit more visual aid to assist you properly.

You could set your light actor to movable to see what happens as far as the visual change. Let me know what you discover.

Thank you,

Andrew Hurley

Here is the enclosure with one wall pulled away to show how it’s made. Note the directional light source to the right, outside the enclosure, and the water just above the floor - not projecting through any of the walls.

Here it is from the top with the wall put back on. This is pre-lighting-build so ignore the odd artefacts.

I’ve removed the ‘rear’ wall here to get a good screenshot. You can see how even with the light completely horizontal there are highlights on the water…through the solid walls and floor.

This illustrates how brilliant these light effects can get.

Let me know if you need anything else to investigate this issue…up to and including a zipped up copy of the test project. I’m happy to help.


UPDATE : I installed 4.8 p2 and found that this no longer seems to be an issue. Thanks!

I’m sorry I was not clear, I’ll work on that in future posts. The problem was that I was getting reflections off the water when the light should not have been able to touch the water at all. I had no lightmass importance volume due to the completely dynamic nature of the lights in my original scene. I was executing a build between changes but since the lighting was all dynamic it didn’t do much.

Having said all that, I suspect that you are unable to recreate the problem because you were using 4.8.x. I installed 4.8 preview2 last nigh and the erroneous reflections have gone away for me too.

Sorry for the trouble. In future I’ll stay on the latest and greatest even if it is unstable.

Hey Eredin,

So I have been attempting to reproduce what you are seeing, but have been unable to do so thus far. Have you been making sure to rebuild your scene after making changes to your lights, as well as adding a Lightmass importance volume?

I am having a hard time understanding what your problem is too. Are talking about the small light bleed between your static meshes or the reflection of the water when the light is at a certain angle?

Thank you,

Andrew Hurley

No worries Eredin,

I would actually suggest always working within a stable version of the engine whenever you are officially developing a project. The preview builds are meant as a test area for new features, and as a way for our users to find bugs with the new features so we can get a fix for them by the official version release.

I was actually working in 4.7.6 because that was the version you reported the issue on :slight_smile: Light bleeding can occur for multiple reasons, but I am glad you have resolved the issue. Let us know if we can help you with anything else!


Andrew Hurley