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Kelp Model Has Really Strange Lighting

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  • Kelp Model Has Really Strange Lighting

    Hello Everyone!

    So I have been tackling this issue for 15 days now, looking at every bit of info I can and I am totally dumb founded on this.
    Whats happening is that My model gets some really strange lighting happening.

    What I mean by this is that the leaves of my kelp seem to have the same lighting on both sides of the leaf.
    The leaves arent "leaves" in speedtree but they are "Mesh Fronds" as well as the ball like model connecting them to the stem.


    Not sure whats happening but I cant figure it out for the life of me. I have tried changing Frond:Flip Normal to None and nothing.
    Everything is UV wrapped and A basic material is placed on as well. I have tried putting my custom material on it and still the issue is there so
    its not the plain materials i use as filler.

    I have tried using leaves and then generating a mesh with a custom material and still the issue arises. I have also tried generating a mesh frond with double sided
    and still nothing.

    I have a photo of the Kelp in UE4 and it has similar lighting in Speedtree that is wrong. I know the issue is in Speedtree because it doesnt look right in there.


    I also have set the normals of my leaves to be facing off its face. ALSO tried changes normal to face straight up at one point to work lighting on both sides but still
    nothing has worked.


    I hope this is enough information for someone to help but im at a total loss and even tried making a new file and redoing the kelp and i still get the same issue...

    ALSO I have tried disconnecting the Two Sided node in UE4 and still nothing... This issue is killing me haha

    Attached Files
    Last edited by MQuags; 01-02-2018, 02:50 PM.

  • #2

    From my understanding, you want to have Transmission applied to the back of the leaf meshes. There were no textures including in the zip, but you need to make sure that there is a Transmission map in the alpha of your Specular map. The white of the Transmission map means a lot of light will shine through, black, means no light will shine through. Once this is applied, you will then want to adjust your leaf normals accordingly, using the 'Mesh' -> 'Normal bias', and the 'Normals' -> 'Alignment' and 'Spread' properties in the Mesh Frond Generator's 'Frond' group. If your 'Normal bias' is set to 1, then 'Normals' -> 'Alignment' and 'Spread' won't work, I would suggest setting 'Normal bias' value to 0 and adjust the 'Alignment' and 'Spread', this should get you closer to proper lighting.

    Hope this helps!


    • #3
      Thank you very much for the reply and advice. The lighting is much better now! It was the Spec issue. Never ran into that problem before but i really appreciate the help!