<div dir="ltr">Hey guys,<div><br></div><div>I'm curious about the implementation of the Velvet shader - I can see that it only reflects light at grazing angles and that the Sigma value is a sort of IOR of some fresnel calculation, but how is it different from simply connecting fresnel/facing ratio to a diffuse shader?</div>
<div><br></div><div>Why the name "Sigma" and not something a little more artist-friendly? Do other renderers use the same term?</div><div><br></div><div>With only a single light source, there's a big black patch near the 0-degree grazing angle, facing directly at camera - is it possible to control the size of this big black patch or is it a fixed constant due to the concept of a velvet shader?</div>
<div><br></div><div>But really I'd just like to know why this shader exists - what it's intended use is and why we can't just create the same effect using other shaders and some fresnel/light vector calculations.</div>
<div><br></div><div>The wiki for the Sigma value is empty, so I'll update it with anything you can tell me.</div><div><br></div><div>Cheers,</div><div>Greg</div></div>