Envmap environment

Description

../../../_images/envmap.jpg

Scene lit by a studio lighting HDR environment

Environment The envmap environment uses a spherical image file for controlling the environment lighting. It uses equirectangular projection, where the horizontal axis is longitude and the vertical axis latitude.

The emission spectrum of the image white point (corresponding to RGB=1,1,1) is defined by a spectrum child element.

By default, the top of the image is oriented towards (0,0,1), and its center to (1,0,0). The envmap orientation can be adjusted by modifying the up ` and :guilabel:`front parameters.

The intensity of the envmap is, by default, equal to the image values, multiplied by the base spectrum. However, it is possible to override the intensity by setting the normalize and value parameters. The normalize parameter can have the following values:

  • Disabled (disabled) : light intensities are directly proportional to the image values and to the base spectrum. value is ignored.

  • Horizontal illuminance (hzillum) : value sets the horizontal illuminance in lux.

  • Average luminance (avglum) : value sets the average luminance over all the sphere in cd/m².

  • Horizontal power (hzpower) : value sets the horizontal energy power in W/m².

  • Average radiance (avgrad) : value sets the horizontal energy power in W·sr/m².

../../../_images/envmap2.jpg

Outdoor scene lit by an envmap emission shader, and a photo based cloudy HDRI image

Children Nodes

Spectrum base

The white point base spectrum emitted by RGB=1,1,1 image pixel values

Image envmap

The equirectangular envmap image

Parameters

name

type

description

up

vec3

The direction where the top of the image (zenith) is oriented in space. Should be orthogonal to front

front

vec3

The direction where the center of the image is oriented in space. Should be orthogonal to up

normalize

list

The intensity normalization mode (see above)

value

real

The value corresponding to the normalize mode

Ocean XML 4.0 example

<environment type="envmap" name="studio">
   <prm up="0 0 1" front="-1 0 0"/>
   <prm normalize="hzillum" value="500"/>
   <spectrum type="blackbody" name="base" temp="6500" gain="1e-05"/>
   <image type="" name="image" path="photo-studio.exr"/>
</environment>