POV-Ray : Newsgroups : povray.binaries.images : Caustic issues Server Time
15 Aug 2024 18:15:09 EDT (-0400)
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From: Oldstench
Subject: Re: Caustic issues
Date: 7 Jun 2002 00:11:24
Message: <3d00326c$1@news.povray.org>
Warp <war### [at] tagpovrayorg> wrote in message news:3d001cc4@news.povray.org...
>   How about this?
>
>
Wow, that looks much better then mine, you are really good....

-Oldstench


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From: Slime
Subject: Re: Caustic issues
Date: 7 Jun 2002 00:34:15
Message: <3d0037c7@news.povray.org>
Wow, that's very nice, though the caustics don't appear quite as realistic
to me in this as they did in the brazil image. I'm sure it's just a matter
of a slightly different shape of ring, though.

 - Slime
[ http://www.slimeland.com/ ]


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From: Samuel Benge
Subject: POV 3.5 Version (ring.jpg 15.8kb)
Date: 7 Jun 2002 02:10:03
Message: <3D0052B2.8030101@caltel.com>
Hello. Here is the POV 3.5 version. I used no lights, only radiosity 
settings and an ambient sphere. Render time was 7m 45s

Here is the POV code:

global_settings{
  max_trace_level 50
  radiosity{
   error_bound .125  count 1575 nearest_count 10
   recursion_limit 1  normal on
   brightness 13.5  gray_threshold 0
   pretrace_start .08  pretrace_end .005
   always_sample on
  }
}

camera{location<0,30,-50> look_at 0 angle 40 }

sphere{<100,50,-50>,40
  pigment{rgb 1}
  finish{ambient 1}
  no_shadow double_illuminate
}

background{rgb .025}

plane{y,-2 pigment{rgb .7} finish{ambient 0} }

union{
  torus{11,1 translate y*1}
  torus{11,1 translate y*-1}
  cylinder{y*-1,y*1,12 open}
  cylinder{y*-1,y*1,10 open}
  pigment{rgb .1}
  finish{reflection .9 ambient 0}
}

Oldstench wrote:

>     My question is this...The first picture (caustinc_ring_2.jpg) represents
> a render I did with Brazil to test its caustics, the second picture
> (torus.jpg) is a photon image that I did in MegaPov just trying to get some
> caustics as a start. But, as you can see..it looks like absolute crap. Why
> is the ring glowing like that, and why are there no caustics in the familiar
> parabolic shape?
>     Thanks - Oldstench
> 
> 
> 


-- 
Samuel Benge

sbe### [at] caltelcom


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Attachments:
Download 'ring.jpg' (16 KB)

Preview of image 'ring.jpg'
ring.jpg


 

From: Apache
Subject: Re: POV 3.5 Version (ring.jpg 15.8kb)
Date: 7 Jun 2002 02:24:40
Message: <3d0051a8$1@news.povray.org>
why 'double_illuminate' ?

--
Apache
POV-Ray Cloth experiments: http://geitenkaas.dns2go.com/experiments/
Email: apa### [at] yahoocom
ICQ: 146690431


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From: Samuel Benge
Subject: Re: POV 3.5 Version (ring.jpg 15.8kb)
Date: 7 Jun 2002 09:46:18
Message: <3D00BDAA.8010701@caltel.com>
Apache wrote:

> why 'double_illuminate' ?


Because I'm silly and left that in by accident. I keep a test scene 
around for this type of thing; I had been testing a similar scene with 
actual photons, and the sphere was origially just used to give the ring 
a nice highlight. A light_source was inside the sphere, and the 
ambient_light was 0, so I had to give the sphere the double_illuminate 
and no_shadow flags.

-- 
Samuel Benge

sbe### [at] caltelcom


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From: Nathan Kopp
Subject: Re: Caustic issues
Date: 7 Jun 2002 23:16:02
Message: <3d0176f2@news.povray.org>
"Slime" <slm### [at] slimelandcom> wrote...
> Wow, that's very nice, though the caustics don't appear quite as realistic
> to me in this as they did in the brazil image. I'm sure it's just a matter
> of a slightly different shape of ring, though.

POV's photons look different in this scene because POV is still shooting
photons from a single point.  You can enable POV to shoot photons from the
area light by adding "photons{area_light}" to the light_source definition.

Also, add "gather 0,200" to the photons block in the global settings (to
smooth the splotchiness introduced by the area-light photons).  (This last
part might require the next RC of POV 3.5... it may not work quite right
with the current release.)

-Nathan


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From: Y Tanabe
Subject: Re: Caustic issues
Date: 8 Jun 2002 01:52:38
Message: <3D019BAE.AD0E970D@kh.rim.or.jp>
Arrange someone's height_field viewer to Mosaic Viewer.

Mega,POV-Ray3.5 version

Y.Tanabe
Kobe,Japan


[Image]

/************************************************************/
// Mega Persistence of Vision Ray Tracer 0.7 Scene Description File
#version unofficial MegaPov 0.7;

global_settings
{
 assumed_gamma 1.8
}

camera
{
   orthographic
   location  <0,0,-5>
   right   <5,0,0>   // length determines size of view
   up    <0,5,0>         // length determines size of view
   direction  <0,0,1>        // length isn't used
   look_at  <0,0,0>
}

sky_sphere {pigment {color rgb <0.25,0.25,0.25>}}

light_source {<0,0,-50> color rgb <1,1,1> parallel point_at <0,0,0>}

light_source {<-50,50,-50> color rgb <1,0,0> * 2.82 parallel point_at <0,0,0>}
light_source {<-50,-50,-50> color rgb <0,0,1> * 2.82 parallel point_at <0,0,0>}

light_source {<50,50,-50> color rgb <0,0,1> * 2.82 parallel point_at <0,0,0>}
light_source {<50,-50,-50> color rgb <1,0,0> * 2.82 parallel point_at <0,0,0>}

light_source {<0,50,-50> color rgb <0,1,0> * 1.414 parallel point_at <0,0,0>}
light_source {<0,-50,-50> color rgb <0,1,0> * 1.414 parallel point_at <0,0,0>}

light_source {<50,0,-50> color rgb <0,1,0> * 1.414 parallel point_at <0,0,0>}
light_source {<-50,0,-50> color rgb <0,1,0> * 1.414 parallel point_at <0,0,0>}

//This determines the final size of the height field. It is used used to scale and
translate tthe HF so it is centered at the origin (<0,0,0>).
#declare square_size  = 5;

//This reads in the height field data
#debug "\nStart height field parsing....\n"


#declare hf =
height_field
{
 png "causticsx.png" //name set by tga,png format
   smooth
  pigment
    {
     gradient y
     color_map
      {
       [0.0 rgb 0]
       [0.0625 rgb 0.0625]
       [0.125 rgb 0.125]
       [0.1875 rgb 0.1875]
        [0.25 rgb 0.25]
        [0.3125 rgb 0.3125]
        [0.375 rgb 0.375]
        [0.4375 rgb 0.4375]
        [0.5 rgb 0.5]
        [0.5625 rgb 0.5625]
        [0.625 rgb 0.625]
        [0.6875 rgb 0.6875]
        [0.75 rgb 0.75]
        [0.8125 rgb 0.8125]
        [0.875 rgb 0.875]
        [0.9375 rgb 0.9375]
        [1.0 rgb <1,1,1>]
      }
    }
 scale <square_size,1,square_size>
 translate <-square_size/2,0,-square_size/2>
}

#debug "\nFinish height field parsing\n"

//create Mesh
#declare interval = square_size / 80; // the higher the number,the finer the grid
patter

#declare CX =  -square_size/2+interval/2;   // do not alter
#declare CZ = -square_size/2+interval/2;    //do not alter
#declare cyl_width = 0.005;                 //width of the cylinder components of the
grid
#declare cyl_tex = texture{pigment {color rgb <1,1,1> }} // texture of the grid itself

#debug "\nStarting grid formation\n"

#declare grid =
union
{
 #while(CX < square_size/2-interval/2)
  #debug concat ( "CX = ",str (CX,3,3)," of ",str(square_size/2,3,3),"\n")
  #while(CZ < square_size/2-interval/2)
   #declare YValue = trace(hf,<CX,20,CZ>,-y);
   #declare YValueX1 = trace(hf,<CX+interval,20,CZ>,-y);
   #declare YValueZ1 = trace(hf,<CX,20,CZ+interval>,-y);
   #if(YValue.x = 0 & YValue.y = 0 & YValue.z = 0)
   //do nothing
   #else
    cylinder {<CX,YValue.y,CZ>,<CX+interval,YValueX1.y,CZ>,cyl_width texture
{cyl_tex}}
    cylinder {<CX,YValue.y,CZ>,<CX,YValueZ1.y,CZ+interval>,cyl_width texture
{cyl_tex}}
   #end
   #declare CZ = CZ + interval;
  #end
  #declare CZ = -square_size/2+interval/2;
  #declare CX = CX + interval;
 #end

 // cap off +X axis
 #declare CX1 =  square_size/2-interval/2;
 #declare CZ1 = -square_size/2+interval/2;
 #while(CZ1 <= square_size/2-interval/2)
  #declare YValue = trace(hf,<CX1,20,CZ1>,-y);
  #declare YValueX1 = trace(hf,<CX1+interval,20,CZ1>,-y);
  #declare YValueZ1 = trace(hf,<CX1,20,CZ1+interval>,-y);
  cylinder {<CX1,YValue.y,CZ1>,<CX1,YValueZ1.y,CZ1+interval>,cyl_width texture
{cyl_tex}}
  #declare CZ1 = CZ1 + interval;
 #end

 // cap off +z axis
 #declare CX2 =  -square_size/2+interval/2;
 #declare CZ2 = square_size/2-interval/2;

 #while(CX2 <= square_size/2-interval/2)
  #declare YValue = trace (hf,<CX2,20,CZ2>,-y);
  #declare YValueX1 = trace (hf,<CX2+interval,20,CZ2>,-y);
  #declare YValueZ1 = trace (hf,<CX2,20,CZ2+interval>,-y);
  cylinder {<CX2,YValue.y,CZ2>,<CX2+interval,YValueX1.y,CZ2>,cyl_width texture
{cyl_tex}}
  #declare CX2 = CX2 + interval;
 #end
}//end union


// objects
union
{
 object {grid translate <0,cyl_width,0>}
 object {hf}
 rotate x*-90
}

//end code
/************************************************************/


Warp wrote:

>   How about this?


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From: Alf Peake
Subject: Re: Caustic issues
Date: 8 Jun 2002 09:19:22
Message: <3d02045a@news.povray.org>
"Y.Tanabe" <tec### [at] khrimorjp> wrote in message
news:3D019BAE.AD0E970D@kh.rim.or.jp...
> Arrange someone's height_field viewer to Mosaic Viewer.
>
> Mega,POV-Ray3.5 version
>
> Y.Tanabe
> Kobe,Japan

Thats very pretty. I'm going to play with that some more.

Alf


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From: Oldstench
Subject: Re: Caustic issues
Date: 8 Jun 2002 13:39:22
Message: <3d02414a$1@news.povray.org>
Dave Bates {[Norman]} <dave[a t]voygr.com> wrote in message
news:3d0129cc$1@news.povray.org...
> This is actually pretty cool.. how did you do that "Reverse image" look?

I guess it has to do with the fact that I am using radiosity and photons? To
tell you the truth I have no idea what caused it.


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From: Dave Bates {[Norman]}
Subject: Re: Caustic issues
Date: 8 Jun 2002 23:22:33
Message: <3d02c9f9@news.povray.org>
I coul dsee radiosity doing that.. :) Thanks for te heads up.. I like the
"inverse" effecgt.. :)

"Oldstench" <tha### [at] hotmailcom> wrote in message
news:3d02414a$1@news.povray.org...
>
> Dave Bates {[Norman]} <dave[a t]voygr.com> wrote in message
> news:3d0129cc$1@news.povray.org...
> > This is actually pretty cool.. how did you do that "Reverse image" look?
>
> I guess it has to do with the fact that I am using radiosity and photons?
To
> tell you the truth I have no idea what caused it.
>
>


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