I’m preparing to teach an Intro to Blender program at my local library, and I’ve run into a rather nasty issue (in 2.75 and older versions). Part of the class will be focusing on a small project–namely, the creation of a glass goblet. However, the Glass BSDF is acting pretty crazy. It’s almost as if the it’s using a fresnel effect, in which is places pure gloss near the edges, and glass near the visible center. The strange part is that it doesn’t do this on a basic sphere, or any other basic object–but does on a goblet-shaped object formed from either a cylinder or a circle (but strangely enough, it doesn’t create this effect on a goblet formed from a sphere). The really odd part is that if I create the interior lining of the cup manually, the effect is still there. But if I create the outer shell by itself and use a solidify modifier the effect disappears–but there’s no refraction. Maybe there’s something I’m missing, but this problem wasn’t around last time I needed a goblet, and I can’t think of any reason glossy material would be showing up as a fresnel effect in glass.
Here’s the photo: