Texturing a sphere: How the heck do you map it evenly?

Discussion in 'Scifi 3D Forum' started by diabloblanco17, Sep 6, 2003.

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  1. diabloblanco17 Jedi Knight

    Member Since:
    Dec 8, 2002
    star 3
    I started making texture maps for planets yesterday, and I've run into a problem. Actually, I ran into this countless times when playing with the planet textures and models on Sci-fi 3D, but I just ignored it then.

    In this case, a picture is worth a thousand words, so I'll provide a few of the former.

    [image=http://www.angelfire.com/alt/3d-duckboy0/Planet_04.jpg]

    As you can see, the texture map I made is curving inwards at the top due to the lack of space compared to the amount of texture. That's using spherical mapping or none at all.

    [image=http://www.angelfire.com/alt/3d-duckboy0/Planet_01.jpg]

    This one is using box mapping. Produces very undesirable results.

    [image=http://www.angelfire.com/alt/3d-duckboy0/Planet_02.jpg]

    And here is an example of spherical mapping with a mirrored texture. It looks incredibly unnatural, although most everything blends better.

    [image=http://www.angelfire.com/alt/3d-duckboy0/Planet_03_Clouds.jpg]

    And the same thing happens with a cloud map, although this can be fixed by lowering the amount of clouds, specifically the ones at the top and bottom.

    So what's the deal? Does anyone know how to compensate for this when making the texture? Or am I just going to have to live with it?
  2. SevenJedi Jedi Master

    Member Since:
    Oct 20, 2001
    star 1
    haven't tried this yet, as i just found this page myself....
    look about half way down and you'll a plugin that may help

    http://www.richardrosenman.com/photoshop.htm
  3. Master_Qel_Droma Jedi Knight

    Member Since:
    Jan 7, 2001
    star 1
    thats the first time ive seen that problem, how big are the maps you are using?
  4. Macho Jedi Master

    Member Since:
    Sep 21, 2001
    star 4
    are you using uvmappin to add your texture to your model?
  5. diabloblanco17 Jedi Knight

    Member Since:
    Dec 8, 2002
    star 3
    Thanks SevenJedi! That worked amazingly well, though I still have to make sure that the right side of the texture map matches the left side.

    And QelDroma, the examples I provided were renders of the planets from Sci-fi 3d, except for the first one, which was a texture map of my own design. All the ones I've downloaded come with one of these problems. The Naboo model is box-mapped, which produces areas where the texture doesn't fit together. The Yavin IV model isn't mapped at all, although that's the equivalent of spherical mapping, and while it doesn't look too bad at the top, it's mirrored material makes it look incredibly unnatural. Geography doesn't follow a set pattern, unless the planet in question is Coruscant. And the Dagobah model has the same problem that mine does: the texture map is scrunched together at the poles. The problem has nothing to do with the size of the maps; it has to do with the fact that a rectangular map cannot be wrapped evenly around a sphere, at least not without heavily distorting the texture.

    And yes, I'm using UVW mapping.
  6. Darksteps Jedi Knight

    Member Since:
    May 15, 2001
    star 3
    one thing you can do to fix it is go into Photoshop or something like that and create a gradient mask at the top and bottom edges for your map and use a MASK material in MAX... with the middle of the mask being white and the very top/bottom edges being gradient to black, which will fade the mapping where it's being distorted... down side, those areas won't have mapping, unless you select the faces in question and give them their own mapping along with a different UVMap application specifically for those areas...

    Darksteps...
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