Sorry Se7enhedd to hijack your thread, but a thread named Glass is where I thought this Q. belongs.
Nilla I have started your HDR glass tute because I have a glass topped table in one of my WIPs. Learning lots thx.

But two questions.

(1)The refraction limit, I put several things on top of my table just to have something to reflect (all odd OBJs I have here and there) Several plain colored lambert materials and Vegeta who I assigned my Glass_S. At a limit of 1-2 I ony had the table top and one glass (left one) looking OK I (other glass things renderefd black and shiny. I upped it to 6 and the ball the table top and the two glasses rendered OK but Vegeta was Black, and there were/are no reflections of him on the table. So I upped the Limit to 20 and ALL my glass went black. Fiddled with settings and couldnt get him to render properly so I took him out. What is the limit 'Limiting' exactly? how many objects in the render can have refractions or how many times a ray of light can be refracted. Like if light gets refracted by a pane of glass and then hits a wine glass (going through two surfaces) is that needing 3 refractions limit. Why did going up to 20 screw up everything?

(2) Any idea why I get this weirdness in the right hand glass?

Want to add this is the best looking image I have ever created in 3D. Thx to both of you (David too).I didnt really get lighting until a few days ago. I still dont really get creating displacement/bump maps. Coloring in my model is the best I can do. And they always look crap when rendered. This table is GOING to have a procedural wood texture (under the glass top) but havent worked that out either. NEway thx again.