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July 23, 2005
Lighting a Sphere
When rendering a sphere, people often put the highlight in the wrong place. The highlight does not belong "at noon."
It is true that a diffuse sphere, like the Moon, will be brightest where the sun shines most directly -- where it is "noon."
However, a sphere with any "shinyness" to it will have its hot spot not at "noon," but in the place on its surface midway between the angle to the light, and the angle to the viewer.
Posted by digital artform at July 23, 2005 11:00 PM
Comments
In my book, "Light for the Artist", now out-of-print, I discussed this reflective phenomenon in highlights on shiny surfaces, and called it the "Reflective Shift."
It occurs too, on less shiny surfaces, where the lightest area on an object can shift from your expected "polar" position, for the same reasons as the highlight.
The position of the lightest area is a function of the spatial relations of light source, object and viewer's eyes.It is not always in the same place on an object, fixed. Very few artists understand this.
I also wrote of the "foreshortening" of the light gradations, which are not always understood in digital art. If you are interested, let me know and I will explain it.
All good wishes,
Ted
Posted by: ted jacobs at March 27, 2006 10:05 PM
I'd like to hear more about that.
I'd particularly like to hear more about this Dictionary of the Human Form you've created.
http://www.tedsethjacobs.com/Dictionary/dictionary1.htm
Posted by: Joseph Francis at March 28, 2006 12:13 AM