Environments are created using High Dynamic Range (sometimes called 32-bit or HDR) panoramic images. They store more brightness
than can be displayed on a conventional computer monitor. They can be created by many different devices, cameras, and software
with a wide range of capabilities. The quality of the HDR input image greatly influences the quality of the custom environment
in Showcase.
You can create your own environment from an HDR image. From the HDR image, create lighting maps, which add lighting to materials
and provide specular and diffuse highlights and reflections.
The source panorama image used to create the IBL Lighting maps must be an HDR image that shows 360 degrees of a scene around
a central point, and 180 degrees vertically (from straight up to straight down). This panorama can be in any of 3 “projections”
for a panorama of this coverage:
- : similar to a world map, where the sphere is mapped to a 2:1 ratio with the poles at the top and bottom edges.
- : similar to an unfolded cube, where each face is a rectilinear view of the cardinal directions (up, down, front, back, etc.).
- : similar to the reflection in a mirrored ball, where the entire scene is warped to fit into a circle within a square image.
Alternatively, instead of starting with an HDR image, you can take an existing environment and add a different backdrop or
scale-independent image, depending on the type of environment you are creating.
- A backdrop is a panoramic image of the environment (typically derived from the same file as the lighting maps, but not HDR)
which is mapped to the visible environment geometry. The panoramic backdrop image must be in a latitude/longitude (equi-rectangular
"map") format and have an aspect ratio of 2:1. Ideally, it should be at resolution 4096 x 2048. The best file format for this
file is PNG (Portable Network Graphics) non-interlaced.
- A scale-independent image is a regular 2D image, typically showing the location where the lighting maps are centered. The
objects in your scene can then be viewed against the image with matching reflections and lighting.
ImportantThe aspect ratio of this image must be exactly 3:4 (4 high and 3 wide).
How to obtain environment image files
There are several ways to obtain backdrop images and lighting maps if you do not want to create your own:
- Contact the Autodesk Consulting team, who can create the image files you need for your customized environment.
- Buy pre-built images from an HDRI image vendor such as SpheronVR (http://www.spheron.com) or Dosch (http://www.doschdesign.com).
- Create your own images using specialized 3D software (such as Autodesk Maya, or Autodesk 3DStudio Max) or with a panoramic
camera rig and image-stitching software (such as Autodesk Stitcher Unlimited) and HDR-enabled software (such as Adobe Photoshop
CS4 Extended http://www.adobe.com, Photomatix Pro http://www.hdrsoft.com, or HDR Shop http://www.hdrshop.com).