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Re: camera angle affects lighting
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From: Keith W. <kw...@cs...> - 2004-07-26 20:03:02
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On Mon, 26 Jul 2004, Dair Grant wrote: > Keith Wiley wrote: > > >Has anyone ever noticed that the camera angle can affect the apparent > >illuimation of surfaces? As I rotate the camera, the brightness of a > >surface changes even though that surface's location in global space, > >and with respect to the environmental lights never changes. > > Not sure if I follow - if you change the camera view, you'll be looking > at a different part of the object, and hence you'd expect the > illumination to change surely? No, look at this example to see what I mean: http://www.cs.unm.edu/~kwiley/illuminationError.jpg The camera is rotating counter clockwise from 1,2,3 and finally 4. At various camera positions, the illumination gets dramatically brighter. This isn't very realistic of course. The surface being illuminated isn't moving at all with respect to the lights. It's also strange that the image is dark in 1 and 4, which are 180 degrees opposed, so it isn't that a particular angle is brightest, and its 180 degree opposite is darkest. Rather, there is a small rotational range, within which the image gets very bright, and at all other rotations the image is dark. The alpha layer is mostly transparant (it puts the white pattern on the brown ground, you can see that I truncate this effect at a certain distance from the blakc "monolith" object in the center), so the proper behavior is the dark appearance and the bright appearance is incorrect. ________________________________________________________________________ Keith Wiley kw...@cs... http://www.unm.edu/~keithw http://www.mp3.com/KeithWiley "Yet mark his perfect self-contentment, and hence learn his lesson, that to be self-contented is to be vile and ignorant, and that to aspire is better than to be blindly and impotently happy." -- Edwin A. Abbott, Flatland ________________________________________________________________________ |
