For now I would like to recommend planar reflections for a flat mirror such as the one shown in the image. The reason being is that the scene capture cube is using a lot of resources capturing every frame and you may need to alter the material further to get correct reflections.
Your scene capture cube is probably using up a lot of memory trying to capture every frame (depending on resolution of render target). The reflections would also be in accurate based of the implementation shown in that video.
Actually this did not solve my problem. I still want to create my mirror using this method. Because I can just disable ‘Capture Every Frame’ which will just capture 1 image before the game starts. This means it’s not using a lot of resources at all unlike you told me. And it looks alot sharper too.
I apologize for assuming you wanted to capture every frame. If you have that unchecked the reason it is green is because that is the default color of an empty cubemap. The reason it is empty is because the level isn’t completely loaded when it gets its first capture.
The fix to this is simple:
In the level blueprint reference the scene capture cube
Drag off and type “capture scene” it will create two nodes
Add a small delay after the begin play (look at screenshot to see how your graph should look)
What you can also do is create a static texture by right clicking the cubemap render target and just use the static texture instead since you don’t plan to capture during gameplay.