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2 sided plane lighting problem

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TheAxiom polycounter lvl 3
lTzXk3y.jpg

The back face of my grass foliage planes are really dark. How can I fix this?

I know how to solve it in the previous Unreal Engine, but I just can't figure it out in UE4.
Custom lighting isn't really available now is it because of PBR? :/

Thank you!

Replies

  • passerby
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    passerby polycounter lvl 12
    shot in the dark, but have you tried editing your foliage plane normals to point upwards?
  • TheAxiom
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    TheAxiom polycounter lvl 3
    passerby wrote: »
    shot in the dark, but have you tried editing your foliage plane normals to point upwards?

    Yeah I have. Sorry. It's not the normals.
    I might just have to wait until the devs add in new features for this.
  • Obscura
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    Obscura grand marshal polycounter
    You say its not the normals, but actually it looks like that to me. Usually you need a this kind of custom normals to get good result on foliage planes:
    uGkjo03.jpg
    I had similar looking issue as yours before I adjusted the normals to look like on this picture, and after I altered them, they looked good. Here is how they look after this modification:
    ZmnvwDb.jpg
    It worth at least a try :) Also, take a look at the foliage section of the wiki here.
  • TheAxiom
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    TheAxiom polycounter lvl 3
    Okay. Well the tutorial I was following from 3D Motive the guy just stuck the normals straight up. Mind you the planes are curved outwards a bit so you can see them from above.

    I presume you are using EU4?

    I'll mess around with it thank you.
  • Obscura
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    Obscura grand marshal polycounter
    Just make the top normals direction parallel to the top faces direction.

    - EU4 or UE3 doesn't matter because the version of the engine doesn't change what the normals do.
  • Ramseus
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    Ramseus polycounter lvl 12
    I spent a while looking at this myself. Two sided materials just look wrong and don't work for plane heavy foliage. It doesn't matter what you do with the normals, the backface of a two sided material just always looks different. And the SSS currently in UE4 isn't very good...

    The normals don't seem to be the issue, I've bent mine every which way, it's Epic's shaders in UE4. My current work around is to just make my geometry double-sided before I export it.
  • Ramseus
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    Ramseus polycounter lvl 12
    Derp. Use a TwoSidedSign node. You put a multiply right before hooking your normals into the material with the TwoSidedSign on one input and your normal map on the other (or just a 0,0,1 vector3 if you have no normal map).

    I thought I tried that before, but I guess not.
  • Kogoshi
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    Kogoshi polycounter lvl 2
    Ramseus said:
    Derp. Use a TwoSidedSign node. You put a multiply right before hooking your normals into the material with the TwoSidedSign on one input and your normal map on the other (or just a 0,0,1 vector3 if you have no normal map).

    I thought I tried that before, but I guess not.
    THANK YOU! 

    I've been searching all day for this fix, took me ages to realise it was the weird backface lighting, then I found your post.  

    Legend!
  • joejexy
    Ramseus said:
    Derp. Use a TwoSidedSign node. You put a multiply right before hooking your normals into the material with the TwoSidedSign on one input and your normal map on the other (or just a 0,0,1 vector3 if you have no normal map).

    I thought I tried that before, but I guess not.
    IT WORKS!!

    Thank you so much for this solution, this has been a problem for me for a while.


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