POV-Ray : Newsgroups : povray.newusers : Solid Mesh problem Server Time
31 Jul 2024 02:19:16 EDT (-0400)
  Solid Mesh problem (Message 1 to 5 of 5)  
From: Kosina Josef
Subject: Solid Mesh problem
Date: 8 Feb 2003 06:14:05
Message: <3e44e67d$1@news.povray.org>
...I mean an object made by mesh triangles, which is not hollow.
Is that right?: (This should be a prism model)
mesh {
        triangle {<0,0,0>, <10,0,0>,<0,0,10>}
        triangle {<0,30,0><10,30,0><0,30,10>}
        triangle {<0,0,0><10,0,0><10,30,0>}
        triangle {<0,0,0>,<0,30,0>,<10,30,0>}
        triangle {<0,0,0>,<0,0,10>,<0,30,10>}
        triangle {<0,0,0>,<0,30,0>,<0,30,10>}
        triangle {<10,0,0>,<0,0,10>,<0,30,10>}
        triangle {<10,0,0>,<10,30,0>,<0,30,10>}
inside_vector <5, 5, 5>
texture { T_Glass3 }
interior {   I_Glass1
                ior 2.42
             dispersion 1.035
             dispersion_samples 50}
      }
 This should do a not-hollow prism, but it looks like it is hollow.
Where is the problem?


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From: hughes, b 
Subject: Re: Solid Mesh problem
Date: 8 Feb 2003 10:24:46
Message: <3e45213e$1@news.povray.org>
"Kosina.Josef" <kos### [at] felcvutcz> wrote in message
news:3e44e67d$1@news.povray.org...
> ...I mean an object made by mesh triangles, which is not hollow.
> Is that right?: (This should be a prism model)

I think what you might be seeing is the fade_distance of the glass interior
making it very dark. You could try removing that identifier and just use
your own fade_distance 30 and fade_power 1 (or 1001 for realistic fading) to
see it is not as darkened. The I_Glass1 has a fade distance of only 2 units
and your prism is much thicker than that.

Having checked this in CSG difference (actual reason for using
inside_vector?) it is definitely not without an interior but I'm not sure it
looks as it should. I'm guessing it is correct though.

Bob


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From: kosinj2
Subject: Re: Solid Mesh problem
Date: 8 Feb 2003 15:40:04
Message: <web.3e456aba1f9e1881cc31a200@news.povray.org>
This one was becoase I want do some comlex shape with mesh,
some cristal for example, and I want be sure that it is filled
with interior... so I tried to do this simple prism and I wondered
why it does not look like wierd. I want a transparent prism wit high ior
and I got something just mirror instead with:
texture { T_Glass3 }
interior {   I_Glass1
                ior 2.42
             dispersion 1.035
             dispersion_samples 50
             fade_distance 30
             fade_power 1
             }
or very dark looking thing with the same code like above, just without the
fade
stuff....

What I am doing wrong?

Josef



hughes, b. wrote:
>"Kosina.Josef" <kos### [at] felcvutcz> wrote in message
>news:3e44e67d$1[at]news.povray.org...
>> ...I mean an object made by mesh triangles, which is not hollow.
>> Is that right?: (This should be a prism model)
>
>I think what you might be seeing is the fade_distance of the glass interior
>making it very dark. You could try removing that identifier and just use
>your own fade_distance 30 and fade_power 1 (or 1001 for realistic fading) to
>see it is not as darkened. The I_Glass1 has a fade distance of only 2 units
>and your prism is much thicker than that.
>
>Having checked this in CSG difference (actual reason for using
>inside_vector?) it is definitely not without an interior but I'm not sure it
>looks as it should. I'm guessing it is correct though.
>
>Bob
>


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From: Warp
Subject: Re: Solid Mesh problem
Date: 8 Feb 2003 17:10:17
Message: <3e458049@news.povray.org>
Kosina.Josef <kos### [at] felcvutcz> wrote:
> ...I mean an object made by mesh triangles, which is not hollow.

  All objects in POV-Ray are hollow. That is, all objects in POV-Ray are
surfaces, and nothing more than surfaces. However, this usually isn't
a problem unless you make a hole to the surface (eg. with clipped_by
or by making a non-closed mesh).
  You should be more specific about what you mean by "it looks hollow",
and you should give a complete (but minimal) scene which demonstrates the
problem you are having (you should minimize the amount of work needed for
people to see your scene).

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -


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From: hughes, b 
Subject: Re: Solid Mesh problem
Date: 8 Feb 2003 20:15:41
Message: <3e45abbd@news.povray.org>
"kosinj2" <kos### [at] felcvutcz> wrote in message
news:web.3e456aba1f9e1881cc31a200@news.povray.org...
> I want a transparent prism wit high ior
> and I got something just mirror instead with:
> texture { T_Glass3 }
> interior {   I_Glass1
>                 ior 2.42
>              dispersion 1.035
>              dispersion_samples 50
>              fade_distance 30
>              fade_power 1
>              }
> or very dark looking thing with the same code like above, just without the
> fade
> stuff....
>
> What I am doing wrong?

Nothing. It is solid for CSG purposes, media too. As Warp had said, objects
are only surfaces. They start off solid though, in the sense that they
interact as if they had substance throughout their interiors. And until the
keyword hollow is applied media or fog will not fill them.

The darkness you see is only from the light fading into it. What you seem to
have perceived as being mirror-like too is probably just the transparency
showing the background (and surroundings) through it. However, in trying
your script out I needed to use a pigment checker pattern surrounding the
scene to see that it was indeed refracting; and a sphere I differenced away
from it made the prism look peculiar too in the area the sphere took away
but it's just a case of refraction making the object complex in appearance.
If you try the following you will see:


#include "glass.inc"

global_settings {
/* important for multiple reflections and/or transparent surfaces */
 max_trace_level 10
}

difference {
mesh {
        triangle {<0,0,0>, <10,0,0>,<0,0,10>}
        triangle {<0,30,0><10,30,0><0,30,10>}
        triangle {<0,0,0><10,0,0><10,30,0>}
        triangle {<0,0,0>,<0,30,0>,<10,30,0>}
        triangle {<0,0,0>,<0,0,10>,<0,30,10>}
        triangle {<0,0,0>,<0,30,0>,<0,30,10>}
        triangle {<10,0,0>,<0,0,10>,<0,30,10>}
        triangle {<10,0,0>,<10,30,0>,<0,30,10>}
inside_vector <5, 5, 5>
}
sphere {10,10}
texture { T_Glass3 }
interior {   I_Glass1
                ior 2.42
             dispersion 1.035
             dispersion_samples 50
             fade_distance 30
             fade_power 1//1001
             media {
              method 2
              scattering {1,.1}
             }
      }
 rotate -45*y
hollow // only here for media to show up
}

light_source {
  <-20, 40, -20>,1
}
camera {
  location  <0, 0, -50>
  look_at   <0, 0,  0>
  right     x*image_width/image_height
}
sky_sphere {
  pigment {
    checker color rgb 1 color rgb 0
 scale .25 }
}


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