Refraction Index - affecting "Solids" in C5? - Polyloop

woodboat · 31st January 2006, 21:29

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

LoneGunman · 31st January 2006, 22:07

As far as it comes to refraction, the only thing it matters is the the angle. Raytracing engines do this on polygon level. Things considered in calculation are material (with it's refraction index) angle of entrance and polygon normal, after that exit angle of the ray itself is calculated. No raytracer, to my knowledge, checks to see if surface is open or closed. The thing which really matters in getting more accurate and natural look in your final render is MaximumRayDepth and Caustics setting in your render room

Charles · 1st February 2006, 04:40

It does not matter if the surface is open or closed. What matters is that each rays go through exactly an even number of surfaces when it crosses your object which is mathematically equivalent to being a closed surface if you consider all directions.

woodboat · 1st February 2006, 07:36

Hmmm....not quite sure what this means. Does it mean that two planes with the same shader applied would make better looking water than one plane? Or would that be one surface curved into a "u" shape so that light would pass through the same shader application twice at least? Please forgive my ingorance here. That would seem to explain why a wine glass, for instance, makes such a lovely likeness. The light (the background image) has to pass through either 2 or more likely four surfaces. Am I getting close?

regards, wb

31st January 2006, 21:29	#1 (permalink)
woodboat Vertex Join Date: Jan 2006 Posts: 27	Refraction Index - affecting "Solids" in C5? 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

31st January 2006, 22:07	#2 (permalink)
LoneGunman SILO abuser Join Date: Jan 2006 Location: Louisville, KY USA Posts: 556	As far as it comes to refraction, the only thing it matters is the the angle. Raytracing engines do this on polygon level. Things considered in calculation are material (with it's refraction index) angle of entrance and polygon normal, after that exit angle of the ray itself is calculated. No raytracer, to my knowledge, checks to see if surface is open or closed. The thing which really matters in getting more accurate and natural look in your final render is MaximumRayDepth and Caustics setting in your render room __________________ My missions are not impossible, I just make them look that way

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1st February 2006, 04:40	#3 (permalink)
Charles Eovia Join Date: Jul 2005 Posts: 53	It does not matter if the surface is open or closed. What matters is that each rays go through exactly an even number of surfaces when it crosses your object which is mathematically equivalent to being a closed surface if you consider all directions.

1st February 2006, 07:36	#4 (permalink)
woodboat Vertex Join Date: Jan 2006 Posts: 27	Hmmm....not quite sure what this means. Does it mean that two planes with the same shader applied would make better looking water than one plane? Or would that be one surface curved into a "u" shape so that light would pass through the same shader application twice at least? Please forgive my ingorance here. That would seem to explain why a wine glass, for instance, makes such a lovely likeness. The light (the background image) has to pass through either 2 or more likely four surfaces. Am I getting close? regards, wb