Mirror Material... how?

Hey there,

there have been a couple of posts about this topic already but none really solved the issue.

I am working on a ArchViz thing and in the bathroom we have a 300x200cm mirror hanging across the wall.

But, Mirrors do not work as they should which I just don’t understand but probably has a good reason in the sourcecode algorithm thingy-ma-bob.

The SSR reflects the sky and ignores anything else (why that is the case is beyond me)

I am not able to put up box and sphere reflections to have it look properly.

The Mirror Scene Capture 2D actor setup ( see here which ends up with something like this ) does not work because the mirror is too big and the distortion is just too much.


Is my only chance to keep fiddling around with the reflection capture actors? Thankfully there is nothing dynamic that is being reflected in the mirror so it does not need to be dynamic…

And an off-topic question: Why does my SSR reflect the sky? There is an entire second part of the house that should block everything. There are numerous walls which have a thickness in front and above the mirror… what am I doing wrong?

Thank you already!


JayCox of on3studio

Screen space reflections are… well, screen space. They only reflect stuff that is visible on your screen. You need to use reflection probes in order to have somewhat more correct reflections (so that stuff doesn’t reflect the sky indoors). Otherwise the materials use the reflection environment of your skylight, which usually is just the sky.
For a mirror you’ll have to use some kind of 2d reflection actor. UDK had this, not sure if UE 4 has it yet.

that is the problem… there is no reflection Actor in UE4 (yet)… :frowning:

The best way to fake it at the moment is to place a camera actor in the mirror plane, facing outward and render that image wth a flipped axis onto the surface…

  • Make a RenderTarget asset in Content Browser
  • Make a Material using the RenderTarget
  • Assign material to the object that should reflect
  • Place a 2D SceneCaptureActor in the world, so that it’s placed where the mirror is, facing frontwards to where you would stand
  • Assign RenderTarget to SceneCapture and configure update rate (careful with per frame updates, can be quite performance hungry)

Have a lot of fun