Screen Space Reflections issue

Development Rendering
1

Hi guys,

I have some issues with Screen Space Reflections. At my work machine they appear correctly, but at home there’s some weirdness going on (please see the attachment). Anyone else has this issue? (Graphics Card: NVIDIA GeForce GTX 660).

Thanks in advance.

1014×575 130 KB

1014×575 138 KB

2

It’s working correctly. The reflections are a post process so it’s only able to reflect whatever is actually rendered

3

Thanks for the reply. Yes, it does reflect only what’s rendered. What I am referring to is how smudged they are. That seems to be a bit odd for me.

4

Hi BrickTop,
Hello! Please report your bug on the UE4 AnswerHub (answers.unrealengine.com/index.html) in the Bug Reports section. This will help us to investigate and track the issue.
Also, please seeanswers.unrealengine.com/questions/12363/how-do-i-report-a-bug.html for more information that could prove useful.

Thank you and have a great day!

5

Which aspect are you referring to as smudged? SSR reacts to roughness of the surface so more rough surfaces will be blurry. The render also uses few samples but they are jittered over time then blended using temporalAnti-aliasing so that having that disabled can affect the look.

6

Thanks for replying, Jordan. I think it’s best if I snapshot the same scene at my other workstation tomorrow, and post it here for comparison.

7

This is expected. Screen space reflections (SSR) are a primitive but fast version of ray tracing. Reflection rays are tracing against the depth buffer of the screen. To do so it steps along the reflection ray testing each point for whether it intersects with the screen geometry. Doing this pixel perfect is extremely expensive because every pixel along the ray would need to be tested. Reflecting something on the other side of the screen could require 1000 pixels to be tested for a single ray. For performance reasons it does far fewer and does some fancy filtering to avoid artifacts that look like slices. That fancy filtering leads to the blurry, noisy or smudged look of reflections.

What Jordan is referring to is glossy SSR which means the blurriness of the reflection is based on the roughness of the material. You can see the difference between the mirror like surface on the left and the rougher surface on the right. The roughness 0.3 surface still reflects but the reflections are blurry. This is correct and desired. The quality of glossy SSR I intend to improve in future releases.

8

The smudging is because those parts aren’t visible and it’s trying to make it not so obvious.