Dear Povray folk,

I wanted to create constructions built from triangle primitives
and spheres at the vertices of the triangles. The spheres have
the same coordinates as the vertices. The rendering by Povray 3
looks odd: the spheres and the vertices of the triangles do not
appear in the same place, especially if they are near the border.

Other problems appeared too. Try the two examples attached.
Any suggestion? Or is it a bug in POV-Ray?
regards

Tamas Gunda
tam### [at] tigriskltehu



----------------------------------------------------------------------
//  First example.
//  The vertices of the triangle primitives have the same coordinates
//  as the spheres. However, their place is different.

//  Thu 9 Sep 1999 19:24:50

#version 3.0
global_settings {assumed_gamma 1.2}
#include "colors.inc"
#include "textures.inc"



camera {location <  1.45,  -0.11, -110>
       direction <0, 0,  7.67>
       look_at <  1.45,  -0.11,  1 >}
light_source {<0, 20,-50> color White shadowless}




//left:
sphere {< -6.127,  3.180,  3.026>  0.1
           texture {pigment {White} finish {Shiny}}}
sphere {< -4.795,  1.678,  2.942>  0.1
           texture {pigment {MandarinOrange} finish {Shiny}}}
sphere {< -7.248,  2.135,  3.171>  0.1
           texture {pigment {White} finish {Shiny}}}

triangle {< -6.127,  3.180, -3.026>,< -4.795,  1.678, -2.942>, <
-7.248,  2.135,  3.171> pigment{ rgb<.75,.75,.7>}}


//middle:
sphere {<  1.067, -0.437, -2.805>  0.1
           texture {pigment {White} finish {Shiny}}}
sphere {<  1.398, -1.938, -2.888>  0.1
           texture {pigment {White} finish {Shiny}}}
sphere {<  0.106, -1.398, -3.529>  0.1
           texture {pigment {White} finish {Shiny}}}

triangle {<  1.067, -0.437,  2.805>,<  1.398, -1.938,  2.888>,<  0.106,
-1.398, -3.529> pigment{ rgb<.75,.75,.75>}}


//right:
sphere {<  9.211, -3.391, -2.592>  0.1
           texture {pigment {White} finish {Shiny}}}
sphere {< 10.153, -2.976, -3.737>  0.1
           texture {pigment {White} finish {Shiny}}}
sphere {< 10.014, -1.501, -3.316>  0.1
           texture {pigment {White} finish {Shiny}}}
sphere {<  9.072, -1.916, -2.171>  0.1
           texture {pigment {Red} finish {Shiny}}}

triangle {<  9.211, -3.391,  2.592>,< 10.153, -2.976,  3.737>,<  9.613,
-2.446,  2.954> pigment{ rgb<.65,.65,.65>}}
triangle {< 10.153, -2.976,  3.737>,< 10.014, -1.501,  3.316>,<  9.613,
-2.446,  2.954> pigment{ rgb<.95,.75,.75>}}
triangle {< 10.014, -1.501,  3.316>,<  9.072, -1.916,  2.171>,<  9.613,
-2.446,  2.954> pigment{ rgb<.75,.95,.75>}}
triangle {<  9.072, -1.916,  2.171>,<  9.211, -3.391,  2.592>,<  9.613,
-2.446,  2.954> pigment{ rgb<.75,.75,.95>}}



background { colour <0, 0, .55> }

//======================================================================================

/*Second example

// In this case the rendering of the triangle primitive looks odd,
// some transparency problem,
// as if the cylinders would be partly opaque, partly transparent.

// On the other hand, if the union is rotated, only the triangle
primitive rotates.
// Without the triangle primitive the cylinders are rotated OK.

//  Thu 9 Sep 1999 20:06:57

#version 3.0
global_settings {assumed_gamma 1.0}
#include "colors.inc"
#include "textures.inc"


camera {location < -0.23,  -0.13, -32.16>
       direction <0, 0,  7.57>
       look_at < -0.23,  -0.13,  1 >}
light_source {<0, 0,-16.08> color White shadowless}

union {



cylinder {<  0.469,   0.254,   0.213>, <  0.498,  -0.921,  -0.773>,
0.15 open
          pigment {White} finish {Shiny} }
cylinder {< -0.967,   0.667,   0.560>, <  0.469,   0.254,   0.213>,
0.15 open
          pigment {White} finish {Shiny}}
cylinder {< -0.967,   0.667,   0.560>, <  0.498,  -0.921,  -0.773>,
0.15 open
          pigment {White} finish {Shiny}}



sphere {<  0.498, -0.921, -0.773>  0.15
           texture {pigment {White} finish {Shiny}}}
sphere {<  0.469,  0.254,  0.213>  0.15
           texture {pigment {White} finish {Shiny}}}
sphere {< -0.967,  0.667,  0.560>  0.15
           texture {pigment {White} finish {Shiny}}}


 triangle {<  0.498, -0.921,  0.773>,<  0.469,  0.254, -0.213>,<
-0.967,  0.667, -0.560> pigment{ rgbt<.65,.85,.65,0.2>} }

 // if you activate rotate, only the triangle is rotated!
 // rotate <30,0,0>
}


 sky_sphere {
    pigment {
      gradient y
      color_map {
        [ -1  color Scarlet ]
        [ 1 color NavyBlue ]
      }
      scale .1

    }
  }
*/

Post a reply to this message

On Fri, 10 Sep 1999 17:35:43 +0200, Zoltan G. Toth wrote:
>Dear Povray folk,
>
>I wanted to create constructions built from triangle primitives
>and spheres at the vertices of the triangles. The spheres have
>the same coordinates as the vertices.

No they don't.  See below.  (followups to povray.general)

>//left:
>sphere {< -6.127,  3.180,  3.026>  0.1
>           texture {pigment {White} finish {Shiny}}}
>sphere {< -4.795,  1.678,  2.942>  0.1
>           texture {pigment {MandarinOrange} finish {Shiny}}}
>sphere {< -7.248,  2.135,  3.171>  0.1
>           texture {pigment {White} finish {Shiny}}}
>
>triangle {< -6.127,  3.180, -3.026>,< -4.795,  1.678, -2.942>, <
>-7.248,  2.135,  3.171> pigment{ rgb<.75,.75,.7>}}

Watch your Z coordinates.  3.026 != -3.026, 2.942 != -2.942, etc.

Post a reply to this message

Zoltan G. Toth <ZGT### [at] tigriskltehu> wrote:
: Or is it a bug in POV-Ray?

  This is not the right newsgroup for asking this question. This newsgroup
is restricted to bug _reports_.
  You should first ask in another group whether it is a bug or not, and only
when you are sure it is, you should post a detailed report here.

  Alan: How about my suggestion of making this group moderated?

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):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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