HDRI

High Dynamic Range Images (HDRI) is a specialhdri image format that accurately specifies brightness values in a scene which create subtle lighting effects without having to specify light positions.  The Shark Rendering Library provides access to a variety of interior, exterior, and studio HDRI maps which can be quickly dragged and dropped into a scene.

The article provides a brief overview of the HDRI types supported by Shark, some interesting links,  and where to place custom images such that they will show up in Shark’s Render Library.

Formats Supported

HDRI images are found in a variety formats.  Shark recognizes the OpenEXR and HDR file formats which may have the following representations:

Vertical and Horizontal Cross Cube Map
A cubic map created by reading a single image which consists of six sub images laid out in the form of an unfolded cube (both ‘vertical’ and ‘horizontal’ versions are supported).

Vertical Strip Cube Map
A cubic map created by reading a single image which consists of six sub images laid out flat into a single image in 1:6 aspect ratio, consisting of 1 by 6 square sub images representing the cube.

Latitude / Longitude Map
Sometimes known as a panorama where the entire environment is flattened into a single flat panoramic image, rather like a map of the globe.

Spherical Map
Usually created by photographing a reflective sphere with a telephoto lens.

Angular Map
Sometimes known as a ‘light probe’ image. It is similar to a spherical map from a reflective sphere, except that the radial dimension is mapped linearly with the angle, instead of being squashed towards edge of the circle. This gives more accurate sampling around the edges of the image.

HDRI Links
Below are some resources for HDRI images that I have found interesting.

Dosch Design
http://www.doschdesign.com/products/hdri

Paul Debevec
http://www.debevec.org/Probes/

Lightworks
http://www.lightworks-user.com/hdri_starter_collection/realtexture.htm

Others…
http://bunkspeedshop.com/HDRILibrary/
http://smashmethod.deviantart.com/art/High-Res-HDRI-Map-Pack-1-9597501
http://www.unparent.com/photos_probes.html
http://www.cs.kuleuven.be/~graphics/index.php/environment-maps
http://www.aversis.be/hdri/hdri-free.htm
http://dativ.at/lightprobes/
http://gl.ict.usc.edu/Data/HighResProbes/

Saving Custom HDRI Maps to Shark

Shark has a special folder for you to place your custom HDRI images.  Place these files into the HDRI folder and relaunch Shark.  These will appear under the RenderLibrary dialog box.  The HDRI folder is in the following locations for PC and MAC.

For PC

C:\Users\<tim>\Documents\Punch!\Shark FX\PhotoRender/Hdri

For Mac

/Users/<tim>/Documents/Punch!/Shark FX/PhotoRender/HDRI

If you have come accross some interesting HDRI links, post a comment with a link.

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