Illustration of BRDF (Bidirectional reflectance distribution function) and BTDF (Bidirectional transmittance distribution function), inspired by <a href="https://en.wikipedia.org/wiki/Image:BSDF05_800.png" class="extiw" title="en:Image:BSDF05 800.png"> BSDF05 800.png</a>
<a href="//commons.wikimedia.org/wiki/User:Twisp" title="User:Twisp">Twisp</a>
This <i>W3C-unspecified</i> <a href="https://en.wikipedia.org/wiki/Vector_images" class="extiw" title="w:Vector images">vector image</a> was created with <a href="https://en.wikipedia.org/wiki/Inkscape" class="extiw" title="w:Inkscape">Inkscape</a> .