| 摘要 |
PURPOSE:To express transparent sense while expressing the shape of a three-dimensional graphic clearly when the three-dimensional graphic is to be expressed as a two-dimensional graphic by dividing the surface of the three-dimensional graphic into plural fine surfaces and calculating the luminance of respective fine surfaces. CONSTITUTION:At the two-dimensional expression of a three-dimensional graphic, an object and an illuminating condition are set up and the object is divided into fine surfaces. Then, the fine surfaces are irradiated under the previously set up condition and a light source, the luminance is calculated, a unit normal vector is found out and a color is determined on the basis of the luminance. Namely, the medium value M of luminance is fixed at first, fine surfaces of which luminance is equal to the medium value M is expressed by a background color and a light source color is gradually mixed with the background color in accordance with the increase of the luminance. When the luminance reaches the maximum value Max, the fine surfaces are expressed only by the light source color, a object color is gradually mixed with the background color in accordance with the decrease of the luminance from the medium value M, and at the time of luminance '0', the fine surfaces are expressed only by the substance color. Consequently, transparent sense can be expressed while expressing the shape of the three-dimensional graphic clearly.
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