Eliminating curved horizon when converting from Sphere to Cube pano

  • I'm trying to convert a series of existing panos to cubes in order to make the iPhone/iPad viewer work properly. The panos are all partial spheres. I took the rendered pano and dropped it onto the "Convert SPHERE to CUBE" droplet, which successfully breaks the image up into 6 square sides. However, the horizon line becomes extremely curved when this happens.

    Is there a way to stop that from happening? I can't figure out if the distortion is coming from the way I shot the pano, or the way I converted it to a cube, or the way that the viewer is handling the pano. I did notice that the "voffset" element that I used in my .XML files in the spherical panos to correct distortion does not seem to have any effect in a cube pano.

    I just need to know what step in the process is resulting in the distortion so that I know if I need to reshoot the pano, or re-render the pano, or reconvert, or whatever I need to do to make it display correctly.

    Thanks!

  • Hi rhea and sacha,

    I use parital spheres too that I convert via the droplet "sphere2cube" without any problems. Without an example it´s a little bit hard to tell what´s the problem with your panos, rhea. Could be a stitching-error, too low detail-settings or that the horizon line was already bad which is´nt that noticable when using a spherical pano.

    Maybe it helps if you open the spherical pano in PS and set the canvas-size to a full cubic size (10000x5000, 5000x2500 etc.) and filling the empty space black.

    If you can´t post the url you´re welcome to send me a PN....

    Best regards
    Nupsi

  • Really? Good to know. Perhaps.
    Then his problem is that they are not centered partials. Not equally the same above and below the horizon. He must figure out where is horizon is and re-add back canvas until the horizon lies centered. But if he remade them into full sphere's this issue becomes self evident.

  • Hi,

    the SPHERE to CUBE droplet (or to be exact the ktransform tool) is basically designed to convert full spherical images to cube images - partial spherical images work too, but only when there horizon is in the middle of the image - a 'voffset' setting to shift the spherical images up or down before converting is not supported,

    to avoid such problem I would recommend stitching the image either as 360x180 or use symmetric vertical cropping (e.g. for a 360x90 images - a -45 to +45 vfov range),

    best regards,
    Klaus

  • Hi All,

    Is it possible to add voffset to the partial spherical image before converting it to Cube ?
    For example , I have image 10112x4333 => 360x154.3 , voffset = -20 for this image.

    How to edit original image to add voffset to it ?


    [Solved] I've added a stripe of pixels to the bottom of the image, where stripeHeight = 20 * 4333 / 154.3

    Einmal editiert, zuletzt von degot (14. Juni 2013 um 01:49)

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