Map-based isotropic BSDF

Description

../../../_images/isomap.jpg

Example of map-based isotropic BRDF measured on a car paint

BSDF This BSDF model uses hemispheric maps representing BRDF values over all reflected directions. Each map corresponds to an incident light direction, and uses equidistant hemispherical projection. Currently, only isotropic BRDFs are supported (the incident light direction only depends on theta).

Any kind of image maps is supported, including high dynamic range images in HDR or EXR format. Spectral EXR are fully supported.

These maps may be generated, or measured directly with a system designed by Eldim SA, which provided the data used for rendering the example, measured on a pink metallic paint sample.

Note

Using this feature requires an Advanced Edition license

Children Nodes

This node is an image list. It may have a variable number of image children representing the reflected light at several indident angles.

Image user-defined

First incident angle

Image user-defined

Second incident angle

Image user-defined

Parameters

name

type

description

thetas

table(real)

List of incident angles for each child image, in degrees

Ocean XML 4.0 example

<bsdf type="isomap" name="brdf">
        <param name="thetas" type="list">
                <row theta="10"/>
                <row theta="20"/>
                <row theta="30"/>
                <row theta="40"/>
                <row theta="50"/>
                <row theta="60"/>
                <row theta="70"/>
                <row theta="80"/>
        </param>
        <image name="1" path="RedPaint_10deg_BRDF.exr"/>
        <image name="2" path="RedPaint_20deg_BRDF.exr"/>
        <image name="3" path="RedPaint_30deg_BRDF.exr"/>
        <image name="4" path="RedPaint_40deg_BRDF.exr"/>
        <image name="5" path="RedPaint_50deg_BRDF.exr"/>
        <image name="6" path="RedPaint_60deg_BRDF.exr"/>
        <image name="7" path="RedPaint_70deg_BRDF.exr"/>
        <image name="8" path="RedPaint_80deg_BRDF.exr"/>
</bsdf>