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What do they mean?

TaozTaoz Posts: 9,979
edited December 1969 in The Commons

I was reading a wikipedia page about shading here, under Distance Falloff it reads:

"Theoretically, two surfaces which are parallel, are illuminated the same amount from a distant light source, such as the sun. Even though one surface is further away, your eye sees more of it in the same space, so the illumination appears the same."

I don't get this part of it: "...your eyes see more of it in the same space..." What do they mean?

http://en.wikipedia.org/wiki/Shading#Distance_falloff

Comments

  • SimonJMSimonJM Posts: 5,997
    edited December 1969

    It does sound weird, but the only way I can make sense of it woudl be if the two planes were large enough to more then fill your field of view. Then with the plane that is further away you are seeing more of it, hence seeing more light reflected off it which would go some way to offsetting the inverse square falloff of the light.

  • TaozTaoz Posts: 9,979
    edited December 1969

    Thanks for your input, it triggered some thoughts here. I think I got it now - what they mean is that one square inch of the screen view represents a larger part of the distant surface than the surface in front, and if the light is evenly distributed on the two regardless of their position a square inch (screen view) of the distant surcafe "contains" more light than a square inch of the one in front. Makes sense?
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  • SimonJMSimonJM Posts: 5,997
    edited December 1969

    Taozen said:
    Thanks for your input, it triggered some thoughts here. I think I got it now - what they mean is that one square inch of the screen view represents a larger part of the distant surface than the surface in front, and if the light is evenly distributed on the two regardless of their position a square inch (screen view) of the distant surcafe "contains" more light than a square inch of the one in front. Makes sense?
    -



    Yes, that was the sort of thing I was trying to relay, but did not think it through to the conclusion you did! :)
  • TaozTaoz Posts: 9,979
    edited December 1969

    OK. :)

    The question is then, will that square inch of the distant surface then look brighter on the screen than the one of the surface in front, per default (without Distance Falloff - linear illumination I guess you could call it)?

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