I want to show a scene in which part is in an underground cavity, as in the
scene below.

The cavity is to be lit from local lights and light coming down the two holes in
the y plane but no light should come through the cross-section z plane. How do I
block this off?

// Persistence of Vision Ray Tracer Scene Description File
// File: Cavity_below_ground.pov
// Vers: 3.7


#include "colors.inc"
#include "stones1.inc"
  camera {
    location <3, 10, -40>
    look_at <0,3 , 0>
    angle 20
  }
  background { color rgb<0.2, 0.4, 0.8>  }
  light_source { <100, 100, -100> color rgb 1 }
  global_settings {assumed_gamma 1.0 }


difference {
  #intersection  {
    plane {y,6 texture { T_Grnt1}}
    plane {z,-4 inverse  texture {T_Stone14}}
                  }
  #union {
    box {<-20,2,.9>,<20,0,-1> }
    box {<-6,10,1>,<-2,1,-1> }
    box {<6,10,1>,<2,1,-1> }
    box {<-5.5,5,-.5>,<5.5,.1,-100> }
    texture {T_Stone15}     }  }

Post a reply to this message

On 19-2-2014 13:48, John Greenwood wrote:
> I want to show a scene in which part is in an underground cavity, as in the
> scene below.
>
> The cavity is to be lit from local lights and light coming down the two holes in
> the y plane but no light should come through the cross-section z plane. How do I
> block this off?
>
> // Persistence of Vision Ray Tracer Scene Description File
> // File: Cavity_below_ground.pov
> // Vers: 3.7
>
>
> #include "colors.inc"
> #include "stones1.inc"
>    camera {
>      location <3, 10, -40>
>      look_at <0,3 , 0>
>      angle 20
>    }
>    background { color rgb<0.2, 0.4, 0.8>  }
>    light_source { <100, 100, -100> color rgb 1 }
>    global_settings {assumed_gamma 1.0 }
>
>
> difference {
>    #intersection  {
>      plane {y,6 texture { T_Grnt1}}
>      plane {z,-4 inverse  texture {T_Stone14}}
>                    }
>    #union {
>      box {<-20,2,.9>,<20,0,-1> }
>      box {<-6,10,1>,<-2,1,-1> }
>      box {<6,10,1>,<2,1,-1> }
>      box {<-5.5,5,-.5>,<5.5,.1,-100> }
>      texture {T_Stone15}     }  }

add at the end of the code the following line:

box {<-10, -10, -5>,<10, 6, -4> no_image}

This closes the front of the cavity, and no_image enables the viewer to 
look inside.

Thomas

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:
> On 19-2-2014 13:48, John Greenwood wrote:
> > I want to show a scene in which part is in an underground cavity, as in the
> > scene below.
> >
> > The cavity is to be lit from local lights and light coming down the two holes in
> > the y plane but no light should come through the cross-section z plane. How do I
> > block this off?
> >
> > // Persistence of Vision Ray Tracer Scene Description File
> > // File: Cavity_below_ground.pov
> > // Vers: 3.7
> >
> >
> > #include "colors.inc"
> > #include "stones1.inc"
> >    camera {
> >      location <3, 10, -40>
> >      look_at <0,3 , 0>
> >      angle 20
> >    }
> >    background { color rgb<0.2, 0.4, 0.8>  }
> >    light_source { <100, 100, -100> color rgb 1 }
> >    global_settings {assumed_gamma 1.0 }
> >
> >
> > difference {
> >    #intersection  {
> >      plane {y,6 texture { T_Grnt1}}
> >      plane {z,-4 inverse  texture {T_Stone14}}
> >                    }
> >    #union {
> >      box {<-20,2,.9>,<20,0,-1> }
> >      box {<-6,10,1>,<-2,1,-1> }
> >      box {<6,10,1>,<2,1,-1> }
> >      box {<-5.5,5,-.5>,<5.5,.1,-100> }
> >      texture {T_Stone15}     }  }
>
> add at the end of the code the following line:
>
> box {<-10, -10, -5>,<10, 6, -4> no_image}
>
> This closes the front of the cavity, and no_image enables the viewer to
> look inside.
>
> Thomas

That does the trick!

Thanks
John

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