Why are reflections always drunk?

expensivea · February 28, 2016, 4:36pm

Hi. ive been getting this problem since i started this project and ive been getting this effect on windows too. i thought id fix it up as i get closer to finishing it but i noticed that this problem doesnt only happen on my windows. its also occuring basically on every reflective surface that i have. why are the reflections kind of inverted or something. its like reflecting itself instead of the thing in front of it? and with windows. it reflects the frame instead of the building (or anything infront of it that it should be reflecting instead. heres a picture of what im talking about.

as you can see the glass panel should be reflecting the wall infront of it. but instead, its like redrawing what is beside it as it is (without reflecting or inverting the objects. at first glance you already know that somethings wrong with the reflection. how can i fix it? thank you very much for your time.

btw the glass material is an instance of a duplicate of the M_glass material from the starter content with a little higher metallic and opacity values (i changed some of the constant nodes to scalar)

anonymous_user_a8ae6e811 · February 28, 2016, 4:48pm

Do you have refraction in your material ?

What it does is simulate light breaking, so you would see what’s in front of the model but slightly skewed.

expensivea · February 28, 2016, 5:10pm

yes i have refraction. i think its 1.4 as it was in the default glass material. i didn’t change it.

but it’s wrong isn’t it? i mean look at it. is so wrong so it’s not reflection at all?

anonymous_user_a8ae6e811 · February 28, 2016, 5:26pm

It’s not really clear from this angle, but I’d try to remove refraction and check if anything changes.

You can see the difference here

expensivea · February 28, 2016, 6:02pm

Thanks RamJ. I think i’ll just do that. But I’m just dying to know, how is glass properly built in ue4? i mean it has to have a refraction value right? If refraction causes this kind of problem then something else must be wrong?

anonymous_user_a8ae6e811 · February 28, 2016, 6:19pm

It’s not really a problem per se, it’s a matter of using it correctly.
In your case, it’s hard to judge since the scene doesn’t have much colour or other objects yet.

It also depends on how you want to use the glass, for example, you can have a thick plate of glass, with the two faces having no refraction, and adding a little refraction on the sides.
Or you can use a texture as an alpha to refract a specific area of of the glass.

As far as reflection goes, from what I’ve encountered, it’s a bit difficult to have both transparency and reflection, but it’s possible with a little work on the material.

Read this to get it to reflect better, and this to learn more about refraction.

The forums and the documents are a great place to learn about everything the engine has to offer, I learn something new there everyday.

Good luck,
**