Ken wrote:
> 
> Marc Schimmler wrote:
> >
> > I'm just wondering if it is possible to make an object which
> > transparency that changes with it's height?
> > Imagine a cylinder which is nearly total transparent at it's bottom and
> > and fully opaque at the top.
> >
> > Any help appreciated from indenters as well as from non-indenters!!! ;-)
> >
> > Thanks in advance,
> > Marc
> > --
> > Marc Schimmler
> 

> Note to Spider:
>   While your example was both a creative and fanciful example of
> blending solid and transparent pigments it really didn't address
> Marc's requirements for a gradual transition from clear to solid.
> Marc may well take note of your example as it does show one of the
> often under used and powerful features of creative texturing. The
> one main fault with your example is that it is difficult at best
> to get a totally transparent blend from one end of an object to the
> other with only two entries in your color map (not to mention the
> large amounts of turbulence used). Three pallet entries are almost
> mandatory and four of more offer considerably greater control of the
> patterns function.
Yes, I understand and agree with you, but I thought your example was so
good at adressing the use of multiple entries in a colour_map that I
don't needed to add those(forgot is abetter explination)

as for the turbulence, it was mostly a joke, but with a more serious
tone to it.

I've taken the right to render an example with both our variants.
I'll convert to jpg. and upload to binaries.images.

Here is the source.
look here in the beginning. I haven't made an attempt to make my code
look like ken's, notr the results.


#version 3.1;
#declare SpidMap =
color_map { 
  [00/10 color rgbt <1,0,0,1> ]
  [01/10 color rgbt <1,0,0,1> ]
  [09/10 color rgbt <1,0,0,0> ] 
  [10/10 color rgbt <1,0,0,0> ] 
}
#declare KenMap =
color_map{
  [00/10 rgbf<1,0,0,1.0>]
  [01/10 rgbf<1,0,0,1.0>]
  [01/10 rgbf<1,0,0,1.0>]
  [02/10 rgbf<1,0,0,0.9>]
  [03/10 rgbf<1,0,0,0.8>]
  [04/10 rgbf<1,0,0,0.7>]
  [05/10 rgbf<1,0,0,0.6>]
  [06/10 rgbf<1,0,0,0.5>]
  [07/10 rgbf<1,0,0,0.4>]
  [08/10 rgbf<1,0,0,0.3>]
  [09/10 rgbf<1,0,0,0.2>]
  [10/10 rgbf<1,0,0,0.0>]
}


global_settings { assumed_gamma 1.0 }
camera {
  location  <0.0, 0.5, -4.0>
  direction 1.5*z
  right     4/3*x
  look_at   <0.0, 0.0,  0.0>
}

sky_sphere {
  pigment {
    gradient y
    color_map { [0.0 color blue 0.6] [1.0 color rgb 1] }
  }
}

light_source { <-30, 30, -30>,color rgb 1 }
plane { y, -1 pigment {color rgb 1} finish{ambient 0 }}

//Top left
cylinder { 
  <0,1,0>,<0,0,0>, 0.6
  texture {
    pigment {
      gradient y
      color_map { SpidMap }
    }
    finish{ specular .2 }
  }
  translate -0.7*x
  translate 0.1*y
}

//lowLeft
cylinder { 
  <0,1,0>,<0,0,0>, 0.6
  texture {
    pigment {
      gradient y
      turbulence <0.3,1.2,0.2>/100
      octaves 3600 //ou _are_ patient, aren't you *smile*
      omega 1/24
      lambda 0.2
      color_map { SpidMap }
    }
    finish{ specular .2 }
  }
  translate -0.7*x
  translate -0.99999*y
}
//low right, Ken's method
cylinder { 
  <0,1,0>,<0,0,0>, 0.6
  texture {
    pigment {
      gradient y
      color_map{ KenMap }
    }
    finish{ specular .2 }
  }
  translate 0.7*x
  translate -0.99999*y
}

//top right, Ken's method
cylinder { 
  <0,1,0>,<0,0,0>, 0.6
  texture {
    pigment {
      gradient y
      turbulence <0.3,1.2,0.2>/100
      octaves 3600 //ou _are_ patient, aren't you *smile*
      omega 1/24
      lambda 0.2
      color_map{ KenMap }
    }
    finish{ specular .2 }
  }
  translate 0.7*x
  translate 0.1*y
}

Post a reply to this message

Thank you Mr. Tyler thank you Spider!

Your advice is a real great help for me!

Povingly,

Marc
-- 
Marc Schimmler

Post a reply to this message

Hi

I think it the Ken Map would work better if you are not just fading from red to
transparent red.
Try to fade to transparent White.

I mean the following


color_map {
    [0 color rgbf <1,0,0,0>]
                ...                            <- i still don't know why it is
nesscesary to make multiple entrys ?
    [1 color rgbf <1,1,1,1>]
    }

Spider schrieb:

> Ken wrote:
> >
> > Marc Schimmler wrote:
> > >
> > > I'm just wondering if it is possible to make an object which
> > > transparency that changes with it's height?
> > > Imagine a cylinder which is nearly total transparent at it's bottom and
> > > and fully opaque at the top.
> > >
> > > Any help appreciated from indenters as well as from non-indenters!!! ;-)
> > >
> > > Thanks in advance,
> > > Marc
> > > --
> > > Marc Schimmler
> >
>
> > Note to Spider:
> >   While your example was both a creative and fanciful example of
> > blending solid and transparent pigments it really didn't address
> > Marc's requirements for a gradual transition from clear to solid.
> > Marc may well take note of your example as it does show one of the
> > often under used and powerful features of creative texturing. The
> > one main fault with your example is that it is difficult at best
> > to get a totally transparent blend from one end of an object to the
> > other with only two entries in your color map (not to mention the
> > large amounts of turbulence used). Three pallet entries are almost
> > mandatory and four of more offer considerably greater control of the
> > patterns function.
> Yes, I understand and agree with you, but I thought your example was so
> good at adressing the use of multiple entries in a colour_map that I
> don't needed to add those(forgot is abetter explination)
>
> as for the turbulence, it was mostly a joke, but with a more serious
> tone to it.
>
> I've taken the right to render an example with both our variants.
> I'll convert to jpg. and upload to binaries.images.
>
> Here is the source.
> look here in the beginning. I haven't made an attempt to make my code
> look like ken's, notr the results.
>
> #version 3.1;
> #declare SpidMap =
> color_map {
>   [00/10 color rgbt <1,0,0,1> ]
>   [01/10 color rgbt <1,0,0,1> ]
>   [09/10 color rgbt <1,0,0,0> ]
>   [10/10 color rgbt <1,0,0,0> ]
> }
> #declare KenMap =
> color_map{
>   [00/10 rgbf<1,0,0,1.0>]
>   [01/10 rgbf<1,0,0,1.0>]
>   [01/10 rgbf<1,0,0,1.0>]
>   [02/10 rgbf<1,0,0,0.9>]
>   [03/10 rgbf<1,0,0,0.8>]
>   [04/10 rgbf<1,0,0,0.7>]
>   [05/10 rgbf<1,0,0,0.6>]
>   [06/10 rgbf<1,0,0,0.5>]
>   [07/10 rgbf<1,0,0,0.4>]
>   [08/10 rgbf<1,0,0,0.3>]
>   [09/10 rgbf<1,0,0,0.2>]
>   [10/10 rgbf<1,0,0,0.0>]
> }
>
> global_settings { assumed_gamma 1.0 }
> camera {
>   location  <0.0, 0.5, -4.0>
>   direction 1.5*z
>   right     4/3*x
>   look_at   <0.0, 0.0,  0.0>
> }
>
> sky_sphere {
>   pigment {
>     gradient y
>     color_map { [0.0 color blue 0.6] [1.0 color rgb 1] }
>   }
> }
>
> light_source { <-30, 30, -30>,color rgb 1 }
> plane { y, -1 pigment {color rgb 1} finish{ambient 0 }}
>
> //Top left
> cylinder {
>   <0,1,0>,<0,0,0>, 0.6
>   texture {
>     pigment {
>       gradient y
>       color_map { SpidMap }
>     }
>     finish{ specular .2 }
>   }
>   translate -0.7*x
>   translate 0.1*y
> }
>
> //lowLeft
> cylinder {
>   <0,1,0>,<0,0,0>, 0.6
>   texture {
>     pigment {
>       gradient y
>       turbulence <0.3,1.2,0.2>/100
>       octaves 3600 //ou _are_ patient, aren't you *smile*
>       omega 1/24
>       lambda 0.2
>       color_map { SpidMap }
>     }
>     finish{ specular .2 }
>   }
>   translate -0.7*x
>   translate -0.99999*y
> }
> //low right, Ken's method
> cylinder {
>   <0,1,0>,<0,0,0>, 0.6
>   texture {
>     pigment {
>       gradient y
>       color_map{ KenMap }
>     }
>     finish{ specular .2 }
>   }
>   translate 0.7*x
>   translate -0.99999*y
> }
>
> //top right, Ken's method
> cylinder {
>   <0,1,0>,<0,0,0>, 0.6
>   texture {
>     pigment {
>       gradient y
>       turbulence <0.3,1.2,0.2>/100
>       octaves 3600 //ou _are_ patient, aren't you *smile*
>       omega 1/24
>       lambda 0.2
>       color_map{ KenMap }
>     }
>     finish{ specular .2 }
>   }
>   translate 0.7*x
>   translate 0.1*y
> }

Post a reply to this message

The simplistic version:

cylinder
{ 0,y,1
  pigment
  { gradient y color_map
    { [0 rgb 1]
      [1 rgbf 1]
    }
  }
}

-- 
main(i){char*_="BdsyFBThhHFBThhHFRz]NFTITQF|DJIFHQhhF";while(i=
*_++)for(;i>1;printf("%s",i-70?i&1?"[]":" ":(i=0,"\n")),i/=2);} /*- Warp -*/

Post a reply to this message

Hi Warp1

Thank you for your answer!

I checked your solution and changed it in two ways.

First a height of 1 for the cylinder leads to the repeating of the
gradient so that both ends are opaque. By using y*0.999 I avoided this.

Second, the effect I was looking for is more the solution spider had
given using the rgbt instead of the rgbf.

I will post at binaries.images two cylinders that show the difference.

Again, thank you

Marc
-- 
Marc Schimmler

Post a reply to this message

I really agree with you, and it works far better twith filter than with
transmit in a gray/white or a colour mixture other than solid colours.
but, I used red, since I had a red colour_map ready, and because I like
the colour.

//Spider

"Lars W." wrote:
> 
> Hi
> 
> I think it the Ken Map would work better if you are not just fading from red to
> transparent red.
> Try to fade to transparent White.
> 
> I mean the following
> 
> color_map {
>     [0 color rgbf <1,0,0,0>]
>                 ...                            <- i still don't know why it is
> nesscesary to make multiple entrys ?
>     [1 color rgbf <1,1,1,1>]
>     }
The multiple entries in the beginning are made so that it will be solid
at a certain area, Therby preventing a transparenccy in the top, and
colour in the bottom. I still don't understand why mr Tyler did the
multiple entries, but I am sure he had a very good reason to do it.

//Spider

Post a reply to this message

Marc Schimmler wrote:
> 
> Hi Warp1
> 
> Thank you for your answer!
> 
> I checked your solution and changed it in two ways.
> 
> First a height of 1 for the cylinder leads to the repeating of the
> gradient so that both ends are opaque. By using y*0.999 I avoided this.

play some with the waveforms here. scallop_wave and sine_wave are nice.

> Second, the effect I was looking for is more the solution spider had
> given using the rgbt instead of the rgbf.
> 
//Spider

-- 
#declare life = rand(seed(42))*sqrt(-1);

Post a reply to this message

Ken wrote:

>   // #Ken       = 1
>   // #indenting = 0
> 
>   cylinder{<0,-1,0>,<0,1,0>,1
>   pigment{gradient y color_map{
>   [0.1 rgbf<1,1,1,1.0>]
>   [0.1 rgbf<1,1,1,1.0>]
>   [0.2 rgbf<1,1,1,0.9>]
>   [0.3 rgbf<1,1,1,0.8>]
>   [0.4 rgbf<1,1,1,0.7>]
>   [0.5 rgbf<1,1,1,0.6>]
>   [0.6 rgbf<1,1,1,0.5>]
>   [0.7 rgbf<1,1,1,0.4>]
>   [0.8 rgbf<1,1,1,0.3>]
>   [0.9 rgbf<1,1,1,0.2>]
>   [1.0 rgbf<1,1,1,0.0>]}
>   translate -.5 scale 2}
>   scale<1,2,1>}

Sorry, you didn't start in column 7.
--
Bob & Kelly Crispen
cri### [at] hiwaaynet
"Verbosity leads to unclear, inarticulate things."
-- Vice President Dan Quayle, 11/30/88

Post a reply to this message

Guess any veteran pover will know you typo'd the 1.8 in there. But for
any newbies coming across this thread, 0.8 is correct for the value in
the next to the last bracket.
Extreme indenting, btw, Ken. Your spaces must be enormous in that font
<sarcasm>.


Ken wrote:
> 
> An untested example:
> 
>                               cylinder{
>                              <0,-1,0>,
>                             <0,1,0>,
>                            1
>                           pigment{
>                          gradient y
>                        color_map{
>            [0.0 rgbf<1,1,1,1.0>]
>            [0.0 rgbf<1,1,1,1.0>]
>            [0.2 rgbf<1,1,1,0.8>]
>            [0.2 rgbf<1,1,1,0.8>]
>            [0.4 rgbf<1,1,1,0.6>]
>            [0.4 rgbf<1,1,1,0.6>]
>            [0.6 rgbf<1,1,1,0.4>]
>            [0.6 rgbf<1,1,1,0.4>]
>            [0.8 rgbf<1,1,1,0.2>]
>            [1.8 rgbf<1,1,1,0.2>]
>            [1.0 rgbf<1,1,1,0.0>]
>                                  }
>                       translate -.5
>                                     }
>                                       }
> 
> How is my indenting now people ?
> 
> --
> Ken Tyler
> 
> mailto://tylereng@pacbell.net

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.htm
 mailto:inv### [at] aolcom?PoV

Post a reply to this message

There's also the more usual method of specifying a greater than 1 (ie.
1.01) for the final color_map entry to keep from having a repeat at the
pov unit.


Marc Schimmler wrote:
> 
> Hi Warp1
> 
> Thank you for your answer!
> 
> I checked your solution and changed it in two ways.
> 
> First a height of 1 for the cylinder leads to the repeating of the
> gradient so that both ends are opaque. By using y*0.999 I avoided this.
> 
> Second, the effect I was looking for is more the solution spider had
> given using the rgbt instead of the rgbf.
> 
> I will post at binaries.images two cylinders that show the difference.
> 
> Again, thank you
> 
> Marc
> --
> Marc Schimmler

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.htm
 mailto:inv### [at] aolcom?PoV

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