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Wonky Mirrored Geo

polycounter lvl 9
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JoshWilkinson polycounter lvl 9
I'm getting some artifacts along the seams of my mirrored geo. The seams don't appear until I build the lighting but how on earth do I fix this issue?

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  • DeadlyFreeze
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    DeadlyFreeze polycounter lvl 17
    Can't really tell you for sure with out seeing a picture but sounds like the ole lightmap specular issue.

    Throw a pic up so we can give you a better answer.
  • MagnificentMicrowave
    Or you didn't make/generate unique lightmap UVs.
  • JoshWilkinson
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    JoshWilkinson polycounter lvl 9
    Can't really tell you for sure with out seeing a picture but sounds like the ole lightmap specular issue.

    Throw a pic up so we can give you a better answer.

    Sorry, completely forgot to throw the pic up. Here it is in engine:
    V2nqf.jpg

    And here is my lightmap, with the resolution boosted pretty high so I really doubt there's much bleed:
    1ZRsJ.png

    And one more for good measure, showing how it bends the normals:
    EerDW.jpg
  • DeadlyFreeze
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    DeadlyFreeze polycounter lvl 17
    Hard to say still, check to see if it still show up after you unplug the norms and rebuild the lighting.
  • JoshWilkinson
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    JoshWilkinson polycounter lvl 9
    Ugh. Good call on unplugging normals for diagnosis. It seems to be a combination of a lightmap and normal issues. And I know how to fix neither :/ Here are my screens in detail lighting mode.

    Lightmap issues:
    5Sem8.jpg

    Funky normals:
    YtqAa.jpg
  • DeadlyFreeze
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    DeadlyFreeze polycounter lvl 17
    It might just all be lightmap specular issues (which aren't really light map issues ironically). Try just turning off lightmap specular in the material misc rollout > allow lightmap specular and see if that fixes it. I'll explain more if that's the actual issue, could be something with the normals hard to tell still.
  • JoshWilkinson
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    JoshWilkinson polycounter lvl 9
    Nah it's not a specular issue. I think I'm just going to have to remodel it all and not ever use mirrored geo. Nobody seems to be able to diagnose this.
  • DeadlyFreeze
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    DeadlyFreeze polycounter lvl 17
    Did you actually test it cause you might be surprised. Since the UV's are inverted the norms are getting hit with different direction lightmap specular and it makes it look backwards even though the norms are perfectly fine.

    5ASd1.jpg
  • JoshWilkinson
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    JoshWilkinson polycounter lvl 9
    Oh man, what you're describing and illustrating appears to be exactly my problem, but the "allow lightmap specular" tick box didn't change it. Just for clarification's sake, it's this guy, right?
    8gWxW.png

    It's encouraging to see people recognize this problem. I was JUST about to remodel different parts when I saw you replied. Would it speed the process up if I emailed you the .fbx?
  • JoshWilkinson
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    JoshWilkinson polycounter lvl 9
    A wonderful thread that deals with this very issue from a couple months ago. It's a fantastic read

    http://www.polycount.com/forum/showthread.php?t=93063

    tl;dr:

    1 The general rule is to not mirror contiguous geo. However if you have to, conceal the seam with more geo.
    2 UV seams should be layed out vertically, not horizontally.
    3 If neither one or two works, turn the Indirect Normal Influence Boost setting down to 0 in the World Properties
  • Xendance
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    Xendance polycounter lvl 7
    Your lightmap UVs look pretty bad. You should try to minimize the amount of UV islands and you have a lot of them.

    Edit: accidentally a word
  • Minato
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    Minato polycounter lvl 5
    You'll have a lot of bleeding with that UV layout(in fact you do!),unless you are going to use a higher resolution lightmap(above 128 ,which is really expensive...as xen said you need to minimize the number of individual islands by modeling contiguous geo and minimizing the number of seams/breaks in your UV,it's a little bit time consuming but the results are worth it...
  • DeadlyFreeze
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    DeadlyFreeze polycounter lvl 17

    1 The general rule is to not mirror contiguous geo. However if you have to, conceal the seam with more geo.
    2 UV seams should be layed out vertically, not horizontally.
    3 If neither one or two works, turn the Indirect Normal Influence Boost setting down to 0 in the World Properties

    While I sort of agree with the don't mirror geo, but it's not entirely correct. The problem is all about UV's and their orientation in relation to each other.

    I explained it in this thread:
    http://www.polycount.com/forum/showthread.php?t=98050

    Mirroring does the same thing as rotating, you change the orientation of the UV's so they aren't matching which causes a seam. There are only 2 good fixes for this. A: fix the UV orientation so all UV's are 'pointing' in the same direction or B: turn off lightmap specular.

    If your extemely desperate you can add a lightmap spec UV as channel 1 and use UV channel 3 for your diffuse/spec/norm/etc. You REALLY shouldn't do that, but it will work.

    The whole UV seams need to be laid out vertically or horizontally is baloney, same goes for the Indirect Normal Influence Boost. Neither of those will do anything to change lightmap specular.

    You should also conisder the object itself, things with really low specular values can be mirrored just fine. Something like dry concrete or matte paint, won't have issues because the lightmap specular wont even show up.
  • JoshWilkinson
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    JoshWilkinson polycounter lvl 9
    Yo Mr. Freeze, thanks a lot. Finally, after 48 hours, I can label my issue "resolved". The room was correct when they all critiqued my light maps. The vertical/horizontal seam orientation does turned out to be a myth (at least it is in my case). But after fixing the light maps and turning off lightmap specular (per your request) I now have a proper looking mesh.

    Thanks a lot to everybody who threw in their two cents!
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