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Transcript of Creating Cube-Maps - Real World Photography Guide.pdfآ  Creating Cube-Maps - Real World...

  • Creating Cube-Maps - Real World Photography To create a cubemap from

    photography, you will need :

    1. A set of images (preferably very high resolution) shot in a way to

    cover a full 360° panorama from

    a single point of view.

    2. A 360° image built from stitching the set from step 1 together -

    usually a spherical, cyndrilical,

    or equirectangular image.

    3. Software that converts combined 360° image from

    step 2 into the cubemap format.

    This 360° Image of coral reef near Heron Island is a equiractangular spherical panorama, meaning if you wrapped

    this rectangular image around the interior geometric faces of a sphere and viewed it from the inside, it would then

    appear undistorted.

    Note that this image is far too low resolution / quality to be acceptable for

    the cubemap format in VR. Remember, whatever resolution a panorama is,

    it will be stretched across a 360 degree view, so always provide as high a

    quality set of starting images as possible.

    When combined, this set of images provide a 360° viewing angle of Bangkok. Note that the exposure is quite different

    between images and that stitching lines are very apparent. For many images, this can be cleaned up automatically,

    but the best cubemaps are created by those willing to provide a lot of high-quality RAW format HDR images and put

    in the time to manually blend exposures between images and remove stitchlines that automatic solutions might miss.

    Once you have your set of images,

    assemble them using the appropriate

    stitching method. There are many

    pieces of software that will auto-stitch

    photos together into a single 360°

    image.

    The best free solution for for fully

    automated image stitching is

    Microsoft’s Image Composite Editor.

    However, If you prefer more manual

    control, you can also do this in

    any recent version of Photoshop

    using the “Photomerge” action

    (File>Automate>Photomerge...)and

    then adjust in the assembled file as

    needed.

    After building the combined image,

    you then need to pass the file into

    another piece of software that will

    convert it into a cubemap, which is an

    image format that provides 6 images

    for each of a cube’s faces. When the

    6 images of a cubemap are applied to

    the proper interior faces of a cube and

    viewed from the inside, the image will

    appear seamless and undistorted.

    The most versatile software package

    for doing this is Pano2VR. Pano2VR

    will allow for many input formats and

    will export out each of the 6 images

    needed to give you a full cubemap.

    In Pano2VR, in the Input column on

    the left, click “Select Input” and match

    the input format to the combined

    360° stitched image file created in the

    previous steps.

    Then in the Output column, click the

    “New Output Format” dropdown and

    make sure it’s on the “Transformation”

    option.

    In the Settings tab, change the “Type”

    dropdown to “Cube Faces,” change

    the “Face Names” dropdown to

    “‘front’..’down’” and choose an image

    size of at least 2048x2048.

    Note that this resolution is

    recommended for each face to

    provide maximum pixel density in

    Gear VR.

    Under the “Output” section at the

    bottom on the “Format” dropdown,

    choose PNG (.png) to ensure minimal

    compression artifacts.

    http://research.microsoft.com/en-us/um/redmond/projects/ice/ http://ggnome.com/pano2vr

  • Up Front Down Back

    Left

    Right

    Creating Cube-Maps - Computer Generated Imagery Creating a cubemap from computer

    generated images (CGI) is much more

    succinct in procedure explaination

    than with photography due to no

    stitch lines and exposure being

    uniform thanks to CG cameras not

    being bound by physical properties of

    lenses and image sensors.

    Most CG shops should have no

    problem rendering out a cubemap

    from various professional software

    solutions, but here is an example

    anyway generated from 3DS Max :

    V-Ray’s box camera option was used

    to render and export this format

    directly out from 3DS Max without

    having to use any additional tools.

    Note that the benefits of using pure

    CGI for generating cubemaps aren’t

    just limited to uniform exposure and

    elimination of stitch lines, but that it

    allows also for additional viewpoint

    possiblities, re-exportation of

    infinintely higher resolution cube faces

    for future use in higher pixel density

    display technology, exportation for

    use on different geometry besides

    that used for cube-maps, and even

    stereoscopic rendering.

    http://www.autodesk.com/products/3ds-max/overview http://www.chaosgroup.com/en/2/index.html