Re: Artistic impression of cloudy structures

*To*: mathgroup at smc.vnet.net*Subject*: [mg121641] Re: Artistic impression of cloudy structures*From*: Roger Bagula <roger.bagula at gmail.com>*Date*: Fri, 23 Sep 2011 03:44:52 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <j5f66o$q7k$1@smc.vnet.net>

The skycolor model by Jacopo Bertolotti is very good! Here is a way that is actually used in ray tracing program like Bryce; you put flat area larger and behind the scene and project you ski image on that: Clear[x, y, z, n, t, r, p, skycolor] x1 = Cos[t]^3*Sin[p]; y1 = Sin[t]^3*Sin[p]; z1 = Cos[p]; w1 = {x1, z1, y1}; skycolor[x_] := RGBColor[x, x, 1]; (* forground model*) g1 = ParametricPlot3D[w1, {t, 0, Pi}, {p, -Pi, Pi}, Axes -> True, Mesh -> None, Boxed -> False, PlotPoints -> 30, TextureCoordinateFunction -> ({2 #4, #5} &), PlotStyle -> Directive[Magenta, Specularity[White, 50], Texture[ExampleData[{"ColorTexture", "Metal4"}]]], Lighting -> "Neutral"] x2 = 4*Cos[t]*p/5; y2 = 4*Sin[t]*p/5; z2 = 0; (* disk to project the sky onto in xz plane*) gb = ParametricPlot3D[{x2, z2, y2}, {t, -Pi, Pi}, {p, 0, 5}, Boxed -> False, Axes -> True, PlotStyle -> {Black, Specularity[White, 10]}, Mesh -> False, ColorFunction -> skycolor] (* put them together with a limited field of vision*) Show[{g1, gb}, PlotRange -> {{-2, 2}, {-2, 2}, {-2, 2}}, Axes -> False] Roger Bagula Roger Bagula