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Al1
04-15-2005, 10:21 AM
In terms of the lighting model, are reflections an addition to the specular component of my calculation or does my material become a blend between a regular
material calculation and the reflection.

Thanks

Al

ZbuffeR
04-15-2005, 02:58 PM
In reality reflection is just a very sharp specular.
In CG they are created separately then added.

mogumbo
04-16-2005, 06:57 PM
I'd say it all depends on the material you're trying to simulate. If a material scatters diffuse light uniformly (is completely diffuse), then adding your reflected light to the diffuse light is appropriate. If it is a material that scatters diffuse light less at shallow viewing angles and reflects more light at shallow viewing angles, then blending the two values might be an easier way to simulate it (that is, of course, if you previously calculated the diffuse as if it was uniformly scattered).

Also, adding your light values together can lead to saturation, which is sometimes pretty ugly if you don't take extra steps to get rid of it.

Jan
04-17-2005, 02:37 AM
Originally posted by mogumbo:
I'd say it all depends on the material you're trying to simulate. If a material scatters diffuse light uniformly (is completely diffuse), then adding your reflected light to the diffuse light is appropriate. If it is a material that scatters diffuse light less at shallow viewing angles and reflects more light at shallow viewing angles, then blending the two values might be an easier way to simulate it (that is, of course, if you previously calculated the diffuse as if it was uniformly scattered).

Also, adding your light values together can lead to saturation, which is sometimes pretty ugly if you don't take extra steps to get rid of it.Interessting. What type of material are you thinking of? At the moment i donīt know, what material has this properties.

Jan.

mogumbo
04-17-2005, 05:19 PM
I believe some types of paints and varnished surfaces exhibit these properties due to internal reflection. Unfortunately, it's hard to observe diffuse light varying with viewing angle because this property is obscured by the outside reflections; I wish I could think of an example material that is not highly reflective on the outside.