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Question about UV grid size in 3DSMax?

MeshMagnet
polycounter lvl 9
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MeshMagnet polycounter lvl 9
I'm having a lightmapping problem in UE4. I'm getting those seams everybody seems to have trouble with... So, I've done some research and it appears you have to line up your UV's with your grid.
Most of the tutorials I've seen just reference Maya. So, how do change the grid size in Max?
Let's say I have a 256 lightmap.
I divide 1/256=0.00390625
Where do I plug in this number?

Is it here:

TssXHx5.jpg
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  • TorQue[MoD]
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    TorQue[MoD] polycounter lvl 19
    I'm wondering this as well. I'm pretty sure the decimal based grid size doesn't work in Max. Also, I've heard that the correct math isn't 1/256 it's actually 1/254 because Unreal uses a 1 pixel border around lightmaps for filtering which means you lose two pixels so you need to divide 1 by 2 less than your lightmap resolution. 
    If I figure out what the correct grid size settings are in Max I'll be sure to let you know.

    Does anyone else on the forums use max for their lightmap UVs?
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  • musashidan
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    musashidan high dynamic range
    Yes, the grid size is where you enter the number,  and render width/height the corresponding lightmap res. Then turn on snap to grid. However, I much prefer to use my own custom textures as the background and snap to pixels instead. 

    Also, @TorQue[MoD] is correct but you can just reduce the lightmap res by 2 within UE instead.
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  • TorQue[MoD]
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    TorQue[MoD] polycounter lvl 19
    musashidan said:
    ...but you can just reduce the lightmap res by 2 within UE instead.
    Oh, so you can just set the lightmap resolution inside UE4 to 126 instead of 128 and this will give the same effect? That makes it easier considering the grid size in max won't go lower than 3 decimal points to begin with. Thanks musashidan!
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  • musashidan
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    musashidan high dynamic range
    @TorQue[MoD] yeah mate. The added 1 pixel border in UE brings it back to 128 again. Even so, this doesn't relieve the fact that lightmaps are a f**ing pain in the arse! :)
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  • TorQue[MoD]
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    TorQue[MoD] polycounter lvl 19
    musashidan said:
    @TorQue[MoD] yeah mate. The added 1 pixel border in UE brings it back to 128 again. Even so, this doesn't relieve the fact that lightmaps are a f**ing pain in the arse! :)
    Glad I'm not the only one who thinks so. I hated vertex lighting with Source Engine but I love it when compared to lightmaps :P
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