Wanilson - 2013-04-05

Hi al.

Recently I've discovered Sunflow,and I got impressed with it quality. Global ilumination is a very realistic render technique!
I am trying to learn Sunflow, and for so I've created a simple scene with some sunflow primitives.
All as fine until I try to do some caustic.

In the scene below there is a glass sphere and just above it there is a spot light, but it casts no caustics trough the glass sphere.

So, I'd like to know what is wrong in the scene. Why there is no caustics?? What is missing fo that?
I am posting my question here because the new forum is not working (since  a long time ago, I believe…)

Scene code: ==========================================================================

image {
    resolution 1280 720
    aa 1 2
    filter triangle
}
trace-depths {
  diff 3
  refl 5
  refr 2
}
photons {
    caustics 1000000 kd 100 0.5
}
gi {
  type igi
  samples 64         % number of virtual photons per set
  sets 1             % number of sets (increase this to translate shadow boundaries into noise)
  b 0.00003          % bias - decrease this values until bright spots dissapear
  bias-samples 0     % set this >0 to make the algorithm unbiased
}
light {
  type sunsky
  up 0 1 0
  east 0 0 1
  sundir 1 1 1
  turbidity 4
  samples 64
}
light {
    type point
    color { "sRGB nonlinear" 1.000 1.000 1.000 }
    power 150
    p 1.7 2.2 -2
}

% |persp|perspShape
camera {
    type   pinhole
    eye    -18.19 8.97 -0.93
    target 1.5 0 +1.5
    up     0 1 0
    fov    30
    aspect 1.777777777777
}
shader {
  name simple_green
  type diffuse
  diff { "sRGB nonlinear" 0.2 0.8 0.2 }
}
%shader {
%  name "glass157"
%  type glass
%  eta 1.57
%  color { "sRGB nonlinear" 1 1 1 }
%}
shader {
    name glass157
    type glass
    eta 1.57
    color { "sRGB nonlinear" 0.9 0.9 0.9 }
%   absorbtion.distance 5.0
    absorbtion.color { "sRGB nonlinear" 1.0 1.0 1.0 }
}
shader {
  name "Mirror"
  type mirror
  refl 1 1 1
}
shader {
  name ciano
  type diffuse
  diff { "sRGB nonlinear" 0 0.9 0.9 }
}
shader {
  name blue08
  type shiny
  diff 0.1 0.1 0.8
  refl 0.1
}
shader {
  name red08
  type diffuse
  diff { "sRGB nonlinear" 0.8 0.2 0.2 }
}
shader {
  name yellow09
  type diffuse
  diff 0.9 0.9 0.1
}
shader {
  name floor
  type diffuse
  diff 0.5 0.5 0.5
}
% Objects definitions ------------------------
% Floor ----------------------------------------
object {
   shader floor
   type plane
   p 0 0 0
   n 0 1 0
}
% A little elephant!! ------------------------------
object {
   shader simple_green
   transform {
      rotatex -90
      scaleu 0.1
      rotatey -25
      translate 1.5 0 +1.5
   }
   type gumbo
   name gumbo_3
   subdivs 6
   smooth false
}
% Teapot ------------------------------------------
object {
   shader Mirror
   transform {
      rotatex -90
      scaleu 0.008
      rotatey 245
      translate -3 0 4
   }
   type teapot
   name teapot_1
   subdivs 4
   smooth false
}
% Esphere -----------------------------------------
object {
   shader glass157
   type sphere
   name mirror
   c 0 0.5 -3
   r 0.7
}
% Julia fractal -----------------------------------
object {
   shader yellow09
   transform {
        scalex 2 rotatey 45 rotatex -55
        translate -1.5 0 2 }
   type julia
   name left
   q -0.125 -0.256 0.847 0.0895
   iterations 8
   epsilon 0.001
}
% Banchoff surface ---------------------------------
object {
   shader blue08
   transform {
      rotatex -90
      rotatey 25
      translate 0 1 4
   }  
   type banchoff
   name myShape
}
% Torus -----------------------------------------
object {
  shader ciano
  transform {
    rotatex 90
    scaleu 0.2
    translate 4 0.4 -2
    }
  type torus
  r 2 4
}
% A wall -----------------------------------------
object {
   shader red08
   type generic-mesh
   name "Plane"
   points 8
       3.1  3.1 0
       3.1 -3.1 0
      -3.1 -3.1 0
      -3.1  3.1 0
      -3.1  3.1 -0.61
      -3.1 -3.1 -0.61
       3.1 -3.1 -0.61
       3.1  3.1 -0.61
   triangles 12
      0 3 2
      0 2 1
      2 3 4
      2 4 5
      3 0 7
      3 7 4
      0 1 6
      0 6 7
      1 2 5
      1 5 6
      5 4 7
      5 7 6
   normals none
   uvs none
}
% =======================================================================

Thank you.