Spherical decal problems in PWX

Discussion in 'SolidWorks' started by ck_8990, Oct 13, 2005.

  1. ck_8990

    ck_8990 Guest

    I am trying to create a rendered animation which will include the earth
    (the planet earth that is). I need to map a world map onto a sphere.
    Unfortunately, I am having trouble getting this to work out accurately.
    I am seeing the following problems:

    a) Seams where the image wraps around the sphere. I cannot find the
    correct combination of variables to get the image to map without a
    noticeable seam. It looks as though the image is correctly stretching
    around the sphere, except for the seam where the image looks
    "squished". It doesn't matter if you type in explicit values for the
    image size or use the stretch to fit option, the seam is still there.
    This is not acceptable as I was planning to have the model rotate in
    the animation so I can't just hide the seam at the far side of the
    model. Is there a specific ratio of decal length to width that will
    result in a correctly mapped decal with no seam? I suspect that it may
    be necessary to use a mask to accomplish this but would prefer not to
    have to do endless experiments to get the correct shape.

    B) Blurring of the decal when rendered. The decal looks good in the
    preview window and when the part is not rendered. The file size is
    sufficient to show a good level of detail. However, when the model is
    rendered the decal suddenly becomes very pixellated and blurry, almost
    like the resolution has been cut in half. I have never seen this
    before in PWX.

    I am using SWX2006 SP0.
     
    ck_8990, Oct 13, 2005
    #1
  2. ck_8990

    That70sTick Guest

    A flat decal on a spherical surface will get squished, deformed,
    wrinkled, and/or torn. It just isn't mathematically possible to do
    without this happening.

    You may be able to get the computer to compromise a little better. Try
    chopping off the poles so that there is a flat at the top and bottom of
    the "world". Also do the same with your decal.

    My theory:
    While there will still be distortion, you will be avoiding the
    singularity that occurs when wrapping at the poles.
     
    That70sTick, Oct 13, 2005
    #2
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