球の中に media を使用して空を描画します。
//**********************************************************************************
#local Cv1=< 0.09, 0.30, 0.51 >;
#local Cv2=< 0.51, 0.09, 0.30 >;
#local Cv3=< 0.30, 0.51, 0.09 >;
#declare M_sky =
media { emission 0.015 intervals 80 samples 1, 1 confidence 0.9 variance 0.1
density { bozo turbulence 0.6 octaves 8 lambda 4 omega 0.6
color_map { [ 0.0 rgbt < 0, 0, 0, 1 > ]
[ 0.1 color rgb Cv1 ]
[ 0.4 color rgb Cv2 transmit 1 ]
[ 0.5 color rgb Cv3 transmit 1 ]
[ 0.6 color rgb Cv2 transmit 1 ]
[ 0.9 color rgb Cv1 ]
[ 1.0 rgbt < 0, 0, 0, 1 > ] }
rotate 180*y rotate -90*x scale < 12, 1.5, 12 >*25 } }
#declare Big_sky =
sphere { < 0, 0, 0 >,100 hollow
pigment { color rgbf < 1, 1, 1, 1 > } finish { ambient 0 diffuse 0 }
interior { media { M_sky } } }
object { Big_sky }
//**********************************************************************************
