Disappointing render results with POVRAY

example.pov

            #include "colors.inc"
            #include "textures.inc"

            global_settings { 
               assumed_gamma 1.0
radiosity {
brightness 2.2
count 300
error_bound 0.15
gray_threshold 0.0
low_error_factor 0.2
minimum_reuse 0.015
nearest_count 10
recursion_limit 5
#if (version>3.1)
adc_bailout 0.01
max_sample -1.0
media off
normal off
always_sample 1

pretrace_start 0.08
pretrace_end 0.01
#end
}

            }

            #default {finish {ambient 0}}
        
              camera {
                location <5000, 1800, 10000>
                look_at  <0, 0,  0>
            }                                             
            
            
light_source{<15000,25000,25000> color rgb<1,1,1> }
sky_sphere {
  pigment {
    gradient y
      color_map {
        [ 0.5  color CornflowerBlue ]
        [ 1.0  color MidnightBlue ]
        }
    scale 2
    translate -1
    }
  emission rgb <0.8,0.8,1>
  }            
            
            
union { union { union { union { union { union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <725.0,0.0,0.0> 
 }

union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <-725.0,0.0,0.0> 
 }

union { box { <700.0,25.0,50.0> , <-700.0,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,1175.00,0.0> 
 }

union { box { <700.0,25.0,50.0> , <-700.0,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,-1175.00,0.0> 
 }
 
 rotate <0,0,0> 
 
 translate <-750.0,0,0> 
 }

union { union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <725.0,0.0,0.0> 
 }

union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <-725.0,0.0,0.0> 
 }

union { box { <700.0,25.0,50.0> , <-700.0,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,1175.00,0.0> 
 }

union { box { <700.0,25.0,50.0> , <-700.0,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,-1175.00,0.0> 
 }
 
 rotate <0,0,0> 
 
 translate <750.0,0,0> 
 }
 
 rotate <0,90,0> 
 
 translate <-2025.0,100.0,0.0> 
 }

union { union { union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <725.0,0.0,0.0> 
 }

union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <-725.0,0.0,0.0> 
 }

union { box { <700.0,25.0,50.0> , <-700.0,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,1175.00,0.0> 
 }

union { box { <700.0,25.0,50.0> , <-700.0,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,-1175.00,0.0> 
 }
 
 rotate <0,0,0> 
 
 translate <-750.0,0,0> 
 }

union { union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <725.0,0.0,0.0> 
 }

union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <-725.0,0.0,0.0> 
 }

union { box { <700.0,25.0,50.0> , <-700.0,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,1175.00,0.0> 
 }

union { box { <700.0,25.0,50.0> , <-700.0,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,-1175.00,0.0> 
 }
 
 rotate <0,0,0> 
 
 translate <750.0,0,0> 
 }
 
 rotate <0,90,0> 
 
 translate <2025.0,100.0,0.0> 
 }

union { union { union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <641.66666666666666666666666665,0.0,0.0> 
 }

union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <-641.66666666666666666666666665,0.0,0.0> 
 }

union { box { <616.66666666666666666666666665,25.0,50.0> , <-616.66666666666666666666666665,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,1175.00,0.0> 
 }

union { box { <616.66666666666666666666666665,25.0,50.0> , <-616.66666666666666666666666665,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,-1175.00,0.0> 
 }
 
 rotate <0,0,0> 
 
 translate <-1333.3333333333333333333333334,0,0> 
 }

union { union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <641.66666666666666666666666665,0.0,0.0> 
 }

union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <-641.66666666666666666666666665,0.0,0.0> 
 }

union { box { <616.66666666666666666666666665,25.0,50.0> , <-616.66666666666666666666666665,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,1175.00,0.0> 
 }

union { box { <616.66666666666666666666666665,25.0,50.0> , <-616.66666666666666666666666665,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,-1175.00,0.0> 
 }
 
 rotate <0,0,0> 
 
 translate <0.0000000000000000000000000,0,0> 
 }

union { union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <641.66666666666666666666666665,0.0,0.0> 
 }

union { box { <25.0,1200.00,50.0> , <-25.0,-1200.00,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <-641.66666666666666666666666665,0.0,0.0> 
 }

union { box { <616.66666666666666666666666665,25.0,50.0> , <-616.66666666666666666666666665,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,1175.00,0.0> 
 }

union { box { <616.66666666666666666666666665,25.0,50.0> , <-616.66666666666666666666666665,-25.0,-50.0>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.0,-1175.00,0.0> 
 }
 
 rotate <0,0,0> 
 
 translate <1333.3333333333333333333333332,0,0> 
 }
 
 rotate <0,0,0> 
 
 translate <0.0,100.0,1525.0> 
 }
 
 rotate <0,0,0> 
 
 translate <0,0,0> 
 }

union { box { <2000.0,25.0,1500.0> , <-2000.0,-25.0,-1500.0>  
    pigment {color Brown} 
    }
 
 rotate <0,0,0> 
 
 translate <0,-1075.0,0> 
 }

union { union { box { <2150.00,150.0,1575.00> , <-2150.00,-150.0,-1575.00>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <0.5,1450.50,0.5> 
 }

union { box { <2150.00,50.0,1575.00> , <-2150.00,-50.0,-1575.00>  pigment {color White} }
 
 rotate <0,0,0> 
 
 translate <-0.5,-1150.50,-0.5> 
 }
 
 rotate <0,0,0> 
 
 translate <0.50,0.5,75.50> 
 }
 
 rotate <0,0,0> 
 
 translate <0,-400.0,1500> 
 }

union { union { plane { <0,0,-1>,0 pigment {color Green} } 
 rotate <270,0,0> 
 
 translate <0,0,0> 
 }

union { box { <4000.0,1600.00,2500.0> , <-4000.0,-1600.00,-2500.0>  
    texture{
     pigment{ brick
              color White
              color rgb<0.8,0.25,0.1>
              // color mortar, color brick
              brick_size <250, 52.5, 125 >
              // format in x-,y-,z- direction
              mortar 10 // size of the mortar
            }
     normal { wrinkles 0.75 scale 10}
     finish { diffuse 0.9 phong 0.2 ambient 0}
     } // end of texture
    
    
    }
 
 rotate <0,0,0> 
 
 translate <0,1600.0,-2500> 
 }
 
 rotate <0,0,0> 
 
 translate <0,-1600,0> 
 }
 
 rotate <0,0,0> 
 
 translate <0,0,-500.0> 
 }