TUD Organische Chemie

Immel

Graphics

Povray 3.5

tracevines

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Example Graphics

(low quality jpg-image only)

Example file (tracevines.pov):

// Persistence of Vision Raytracer Version 3.5 Scene Description File
// File: tracevines.pov
// Author: Ron Parker
// Description: Algorithm shamelessly lifted from
// "Modeling Plants With Environment-Sensitive Automata"
// Proceedings of Ausgraph '88, pages 27-33
// by James Arvo and David Kirk
//
//*******************************************

#macro Interfere( A, B, Object )
#local N=<0,0,0>;
#local I=trace( Object, A, B-A, N );
(vlength(N) & (vlength(I-A)#end // macro

#macro FindTmp( CurPt, Normal, Object, RandSeed )
#local More = 1;
#local Safety = C3;
#local Q = <0,0,0>;
#while ( More & Safety )
// select random unit T orthogonal to Normal
#local T = ;
#local T = T-vdot(T,Normal)*Normal;
#if ( vlength(T))
#local T = T/vlength(T);
#local Safety = Safety-1;
#local Q = CurPt + C2 * T;
#local More = Interfere( CurPt, Q, Object );
#end // if
#end // while
#if (Safety)
Q;
#else
<0,0,0>;
#end // if
#end // macro

#macro Draw( CurPt, NewPt, Normal, NewNormal )
union {
sphere {CurPt, R1}
sphere {NewPt, R1}
cylinder {CurPt, NewPt, R1}
#local Pr = vcross(NewPt-CurPt, NewNormal );
#local Pl = vnormalize(NewPt-CurPt);
#local Or = vnormalize(.3*NewNormal+.7*Pl);
triangle {NewPt, NewPt+LL*Or, NewPt+.5*LL*Or+.5*LW*Pr
translate R1*NewNormal}
triangle {NewPt, NewPt+LL*Or, NewPt+.5*LL*Or-.5*LW*Pr
translate R1*NewNormal}
texture {
pigment {color green 1}
}
}
#end // macro

#macro Grow( Start, Normal, Object, RandSeed )

#local Continue = 1;
#while ( Continue )
#ifndef (Watchdog)
#local Watchdog = C8;
#else
#declare Watchdog = Watchdog - 1;
#end // ifndef

#ifndef (Gen)
#local Gen = 0;
#else
#local Gen2 = Gen+1;
#local Gen = Gen2;
#end // if

#local Continue = 0;
#local Branch = 0;

#if ( Watchdog )

#local CurPt = Start + C1 * Normal;
#local NewTmp = FindTmp( CurPt, Normal, Object, RandSeed )
#if (vlength( NewTmp ))

#local Dist = 9999;
#local NewRoot = Start;
#local NewNormal = Normal;
#local NewPt = CurPt;
#local Iter = C3;
#while (Iter)
#local R = rand(RandSeed)-.5>+Bias;
#local N = <0,0,0>;
#local Int = trace( Object, NewTmp, R, N );
#if ( vlength(N) )
#local CurDist = vlength( Int-Start );
#local TestPt = Int + C1 * N;
#if ( (CurDist < Dist) & (CurDist < C4) &
!Interfere( CurPt, TestPt, Object ))
#local Dist = CurDist;
#local NewRoot = Int;
#local NewNormal = vnormalize(N);
#local NewPt = Int+ C1 * N;
#end // if shorter dist
#end // if N
#local Iter = Iter-1;
#end // while Iter
#if ( vlength(CurPt-NewPt))
Draw( CurPt, NewPt, Normal, NewNormal )
#if (rand(RandSeed) > C5 & Gen < C7)
#local Continue = 1;
#if (rand(RandSeed) #local Branch = 1;
#end // if branch
#end // if continue
#end // if new point
#end // if NewTmp found
#end // if watchdog

#if (Branch)
Grow( NewRoot, NewNormal, Object, RandSeed )
#end // if branch
#local Start = NewRoot;
#local Normal = NewNormal;
#end // while continue
#end // macro

#declare Fence = union {
cylinder {-2.2*x, <-2.2,2,0>, .2}
cylinder {0, <0,2,0>, .2}
cylinder {2.2*x, <2.2,2,0>, .2}
cylinder {<2.2,1.7,0> <-2.2,1.7,0> .1}
cylinder {<2.2,1,0> <-2.2,1,0> .1}
plane {y 0 pigment {bozo color_map {[0 rgb <1,.8,.5>][1 rgb <.8,.5,.1>]}}}
translate -.02*y
texture {
pigment {
color rgb <.5,.25,.1>
}
}
}

#declare C1 = .02; // distance of the vine from the object it grows on
#declare C2 = .05; // Approximate step distance
#declare C3 = 60; // number of attempts to find a surface to take root
#declare C4 = .1; // Maximum jump between roots
#declare C5 = .05; // probability of quitting after each generation
#declare C6 = .3; // probability of branching after each generation
#declare C7 = 150; // absolute maximum generations
#declare C8 = 10000; // absolute maximum generations along all branches

#declare R1 = .01; // radius of vine

#declare LL = .1; // length of leaf
#declare LW = .1; // width of leaf

#declare Bias = <-.2,.4,0>;
#declare RandSeed = seed(347);

#declare Sa=array[12] {
<-2,0,0>,<-2.4,0,0>,<-2.2,0,.2>,<-2.2,0,-.2>, // left post
<2,0,0>,<2.4,0,0>,<2.2,0,.2>,<2.2,0,-.2>, // right post
<-.2,0,0>,<.2,0,0>,<0,0,.2>,<0,0,-.2> // center post
}

#declare Na=array[12] {x,-x,z,-z,-x,x,z,-z,-x,x,z,-z}

#declare Count=0;

#while (Count<12)
#debug concat("plant ",str(Count+1,0,0), "\n")
Grow( Sa[Count], Na[Count], Fence, RandSeed )
#declare Count=Count+1;
#end

object {Fence}
light_source {<-20,20,-20> rgb 1}
camera {location <-2,3,-5> look_at y}