Hello everyone.
I took a look at Unrea Engine paper and I see a picture that it was called specular D modification. I didn't find anything on how to achieve the effect .
Here's a shot : http://uploadax.com/images/28835413724170240386.jpg
I want to know how is it possible to create that effect ? Actually lengthen the specular part ?
I believe that the older "area light" stuff they presented back then isn't actually used anymore. It was a really rough approximation, and their specular model in general had a few problems. If you go with a "standard" microfacet BRDF with proper D + G + F terms, you should get "lengthy" reflections without doing any special work. You can look at my course notes from SIGGRAPH for an example of a GGX-based microfacet specular model, and you can also look at Brian Karis's course notes from the same course to see a more recent update on what they're doing for UE4.
