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Hi,
I hope someone has an easy solution for my problem.
I am trying to make some images for a description of the standard model of
particle physics, such as neutron, protons, quarks, electrons etc.
The images have to be combined and used in print. Apart from the previous
mentioned CMYK problem (do those colors turn ugly, yagh) I have a problem
with the background. I would like our illustrator to be able to cut out the
'solid' objects and place them in the desired color background. A good
contrast between the edges and the background helps to make the result
appear smooth.
OK, I know I can make all the background colors in POV-ray that I want, but
it is difficult to obtain the desired color in RGB as I can't predict what
it will be in CMYK, and the colors have to fit in the lay-out (colors of
other images, photographs etc.).
I thought I would render all objects with a white background. When the
background is blue or black, they look nice. However, when I choose a white
background, they suddenly appear to be very pale. Like a color slide film
that has received too much light. What is the best way to proceed? A problem
is that some objects, such as the trajectory of an electron, should be
transparent.
Should I instead of background use a plane (some shadows would be nice,
maybe), should I change the lights or other settings or is there another
possibility to obtain the desired result with a coloured background.
Looking forward to advise
Erick
Here follows an example of such a scene file, three quarks in a
'transparent' sphere
global_settings { assumed_gamma 2.2 }
#include "colors.inc"
#include "glass.inc"
#include "metals.inc"
camera{location <0,8,-20> look_at 0}
background {color White}
light_source{<100,100,-100> White}
// create a point "spotlight" (conical directed) light source
light_source
{
0*x // light's position (translated below)
color rgb <1,.7,.7> // light's color
spotlight // this kind of light source
translate <40, 80, -40> // <x y z> position of light
point_at <0, 0, 0> // direction of spotlight
radius 5 // hotspot (inner, in degrees)
tightness 50 // tightness of falloff (1...100) lower is softer,
higher is tighter
falloff 8 // intensity falloff radius (outer, in degrees)
}
#declare Media = media {
emission 0.05
intervals 5
samples 1, 10
confidence 0.9999
variance 1/1000
density {
spherical
ramp_wave
turbulence 0.1
color_map {
[0.0 color rgbt <0, 0, 0,.99>]
[0.1 color rgbt <1, 0, 0,.95>]
[1.0 color rgbt <1, 1, 0,.9>]
}
}
}
sphere {<0 ,0,0>,.5 pigment {color rgb <1,.2,.2>} translate
<1.5,1.5,-1.5>no_shadow}
sphere {<0 ,0,0>,.5 pigment {color rgb <.2,.2,.7>} translate
<-1,-1.5,1.3>no_shadow}
sphere {<0 ,0,0>,.5 pigment {color rgb <.2,.2,.7>} translate
<0,.5,-1>no_shadow}
sphere { <0, 0, 0>, 5
pigment { rgbt<1, 1, 1, 0.8> }
finish {
ambient 0.0
diffuse 0.0
phong 1.0
phong_size 200
}
interior { ior 1.2 }
hollow yes
}
sphere { 0, 1
pigment { color rgbf<1, 1, 1, 1> }
finish { ambient 0 diffuse 0 }
interior { media { Media } }
scale 5
hollow
}
Post a reply to this message
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Erick wrote:
>
> Hi,
> I hope someone has an easy solution for my problem.
>
> I am trying to make some images for a description of the standard model of
> particle physics, such as neutron, protons, quarks, electrons etc.
>
> The images have to be combined and used in print. Apart from the previous
> mentioned CMYK problem (do those colors turn ugly, yagh) I have a problem
> with the background. I would like our illustrator to be able to cut out the
> 'solid' objects and place them in the desired color background. A good
> contrast between the edges and the background helps to make the result
> appear smooth.
>
> OK, I know I can make all the background colors in POV-ray that I want, but
> it is difficult to obtain the desired color in RGB as I can't predict what
> it will be in CMYK, and the colors have to fit in the lay-out (colors of
> other images, photographs etc.).
>
> I thought I would render all objects with a white background. When the
> background is blue or black, they look nice. However, when I choose a white
> background, they suddenly appear to be very pale. Like a color slide film
> that has received too much light. What is the best way to proceed? A problem
> is that some objects, such as the trajectory of an electron, should be
> transparent.
>
> Should I instead of background use a plane (some shadows would be nice,
> maybe), should I change the lights or other settings or is there another
> possibility to obtain the desired result with a coloured background.
>
> Looking forward to advise
>
> Erick
>
After rendering your example with various coloured backgrounds, the
only problem I see is the emission type media which is trying to add
colour
to the white background.
Any colour components which are greater than 1.0 when the pixels are
written to disk are clamped to the range 0..1. Therefore an emitting
media can have no effect on a white background. Perhaps you could add
an absorbing component to your media or can you get away with a grey
background.
Cheers, PoD.
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nl> wrote: