Creating Cube-Maps - Real World Photography Guide.pdf · Creating Cube-Maps - Real World...

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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.

Transcript of Creating Cube-Maps - Real World Photography Guide.pdf · Creating Cube-Maps - Real World...

Page 1: Creating Cube-Maps - Real World Photography Guide.pdf · Creating Cube-Maps - Real World Photography To create a cubemap from photography, you will need : 1. A set of images (preferably

Creating Cube-Maps - Real World PhotographyTo 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.

Page 2: Creating Cube-Maps - Real World Photography Guide.pdf · Creating Cube-Maps - Real World Photography To create a cubemap from photography, you will need : 1. A set of images (preferably

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Creating Cube-Maps - Computer Generated ImageryCreating 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.