glitch in reflection

I have set up the room, which contains the floor tiles with metallic material. Among the all floor tiles , I kept one floor tile to be rotated at 90 degree (any angle except 0). I also put the box reflection and SSR. By this setup. I got the glitch in the reflection as shown in the figure.

61692-reflection+problem.jpg

Hi -

At first glance it looks like the line separating your Screen Space Reflections and your Reflections backed by the Sphere/Cube Reflection Actor. Try turning off your SSR momentarily and see if the error disappears, if so then you will need to reposition your Sphere actor and/or balance the brightness and quality of the Reflection Actors, Skylight and your SSR.

Thank You

Eric Ketchum

AH, so your reflection capture actor needs to be scaled correctly if you rotate the cube. Can you show me the cube reflection actor selected in your level? My suspicions is that when you rotate the reflection actor box the line of the box is cutting across the picture which will render as you picture show above.

Thank You

Eric Ketchum

Hi -

The only way I can get this to reproduce is to have two box capture actors with no fade distance (fade set to 0) close enough and expansive enough to overlap and they will create the line.

Here is an image:

I have also attached my 4.8.3 project with this setup, if you still think that this is still an issue open this test project up and attempted to reproduce the setup with the assets in the project and re-upload here.

Thank You -

Eric Ketchum

[Test Project 4.8.3][2]

Hi -

Let me think you for giving me the updated project, it helped me identify the exact issue here. Unfortunately it is a limitation of the Reflection Environment. It is discussed in great length in the documentation here, Reflections Captures in Unreal Engine | Unreal Engine 5.3 Documentation, Specifically though I want to point out the issue that we are discussing:

It is extremely important to setup your scene’s materials to work well with the Reflection Environment. A flat, mirror surface will reveal the inaccuracies of combining cubemaps projected onto simple shapes. However, curvy geometry or rough surfaces can both obscure these artifacts and provide convincing results. So it is important to use detail normal maps and specify some degree of roughness on materials that will be used in flat areas.

Smooth and Curvy Geometry:

Rough and Flat Geometry:

Smooth and Flat Geometry: [This is the exact example we have set up in our test projects.]

Reflections through this method are approximate. Specifically, the reflection of an object will rarely match up with the actual object in the scene due to projection onto simple shapes. This tends to create multiple versions of that object in reflections as many cubemaps are being blended together. Flat, smooth surfaces that cause mirror reflections will show the error very noticeably. Use detail normal maps and roughness to break up the reflection.

For your particular application, I would suggest as mentioned above adding a detail normal map to your metallic Material or break up the roughness with a scuff map (think smudged glass) to help break up the cube map blending which is generating the incorrect errors.

Thank You

Eric Ketchum