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Noob question about mesh and material culling

So, im trying my best to not give up in unreal engine while i learn. Right now, ive been trying to figure out the entire day why my meshes stop being reflected when they are out of the scope of my camera.

To be specific, i have a really simple room (the default room that comes with the first person template), i created an emissive material, assigned to one of the cubes, placed a reflective material into the walls, and thats about it. If my cube can be seen in the screen, it will reflect on the wall and the emission as well. If i walk to the point i cant see the cube anymore, it wont reflect anymore on the wall…

How to fix this? what setting do i need to change?

Thanks in advance.

Hi, unreal engine uses “Screen Space Reflections” (SSR) which is as the name suggests a Screen Space effect, meaning you will only see reflections of objects that are on your screen.

So if your cube is not on the screen, then you won’t see any reflection of it.
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What you can do is use “Reflection Captures” (Sphere Reflection Capture). The Sphere Reflection Capture captures an image of the scene at it’s position and UE will then use this information to display reflections, when the object is not on your screen.
So basically you would place Sphere Reflection Captures near reflective surfaces.

So when the object is on the screen, UE will use SSR, but when it is not on the screen, then UE will fallback to Reflection Captures.
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Under Learning&Support -> Online Learning you could watch “Lighting Essential Concepts and Effects” -> “Lightning Essentials: Reflections” to get a better feeling of how you would use Reflection Captures.

Well, thanks for the answer. But how is that, in the tutorial im following, the guy does not have that problem, and when im doing the exact same thing, i have this issue? isnt there any other way, even if it cost more performance to make the objects always reflecting? and btw, i dont think i understand. I have a reflection capture sphere, the one that comes with the first person template that englobes the entire level… but i still cant see the reflections. And what if i have a reflective wall that goes the entire level?? i would need to place dozens probably more reflection captures all along???..

I suggest you watch the learning video I mentioned above.

For flat reflective surfaces you can use “Planar Reflections” (never used them so I don’t have any knowledge there), but you will have to enable that in the project settings (and restart the editor) and it will increase your render time. For everything: Ray Tracing :slight_smile:
But with todays hardware Ray Tracing will kill your performance.

One Sphere Reflection Capture takes one image of the scene from the position of the reflection capture. Therefore if your camera is exactly at the position of the Reflection Capture, you will see the reflection (mostly) correct. Therefore you would need to place many reflection captures throughout your level.

And of course Reflection Captures only work for static objects since they capture the scene once. If you spawn objects during the game or have movable objects, you won’t see those in the reflections.
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And I would suggest you watch either the video I mentioned above or some other tutorials to get a feeling of how to use reflection captures.

Is there a way to download the videos or something like that?? i need to go to the page, search for the tutorial, select the part of the course i want to watch, every time i want to keep watching it. Its a bit tedious, honestly. Specially when i cant finish a lesson for whatever reason and i need to keep watching it later… I cant even add it to my favourites because it will send me again to the course selection. Its sort of ridiculous.

Not that I know of.

Well, in that case im not interested in those tutorials. Because i want to re-visit them in the future when i have doubts or i want to deep more into them. And its too annoying in the moment i want to revisit specific topics in those videos. Only thinking that there are many of those tutorials i would like to watch… it give me the creeps. I will need to find something else, thanks anyways. Its a shame that Epic dont allow people to download them for better and fastest access, we are in the year 2020, and people like to have learning tutorials in their hds for really faster access and not relying on a locked webpage to watch them. I was really surprised to discover that they locked the videos completely, heck i cant even change the volume outside the video volume bar either… hahahaha. Ridiculous. In any case, i already knew about how reflectio spheres work, my issue was that i wanted to deactivate the oclusion thing, so i can see objects reflected even if the camera isnt pointing at them. Apparently you cant do that in UE… o.O. And that is not explained in that tutorial anyways.