In some other softwares, a closed poly object is (or at least acts like) a 3d solid when it comes to refraction. I'm trying to figure out whether Carrara needs a closed polygon object to more convincingly make refractions. Planes with refraction look good as well, but does anyone have any experience in comparing planes and "solids" or closed polygon objects?
Here is a link to a complete refraction chart of values for various materials. It was originally published in the Rendo Cinema 4D fourm by Sean Paul - thanks to him - again! (Search "refraction index" at Renderosity Cinema 4D forum for the thread)
http://www.sean-paul.com/c4d/RefractionCharts.zip
regards, wb