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Hello,
I am doing numerical simulations on granular materials in rotating
drums. The particles are approximated by spheres and I investigate
especially the segregation (un-mixing) dynamics when particles of
differnt sizes are used.
In order to present and visualize my scientific research, I use POVRAY
to create PPM-images which are converted to MPG- and AVI-videos using
mpeg_encode or mkavi, respectivly. In experiments, a plexiglas cylinder
is used to allow for visual inspection and I would like to use the same
in the POVRAY scene file. Unfortunately, the picture does not come out
as expected. The "Glass" and "Glass3" textures for the cylinder are far
too dark and "Glass2" seems to be better. Nevertheless, in all three
cases, far too many reflections are visible which lead to a
unpresentable and ununderstandable image.
I included my scene-file as attachement and would like to know if
somebody can point out to me what I did wrong.
Regards,
Gerald
--
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Dr. Gerald H. Ristow
Division of Engineering
Colorado School of Mines
Golden, CO 80401-1887, U.S.A.
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Attachments:
Download 'drum_3d.pov.gz' (34 KB)
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Gerald H. Ristow wrote:
> Hello,
> I am doing numerical simulations on granular materials in rotating
> drums. The particles are approximated by spheres and I investigate
> especially the segregation (un-mixing) dynamics when particles of
> differnt sizes are used.
> In order to present and visualize my scientific research, I use POVRAY
> to create PPM-images which are converted to MPG- and AVI-videos using
> mpeg_encode or mkavi, respectivly. In experiments, a plexiglas cylinder
> is used to allow for visual inspection and I would like to use the same
> in the POVRAY scene file. Unfortunately, the picture does not come out
> as expected. The "Glass" and "Glass3" textures for the cylinder are far
> too dark and "Glass2" seems to be better. Nevertheless, in all three
> cases, far too many reflections are visible which lead to a
> unpresentable and ununderstandable image.
> I included my scene-file as attachement and would like to know if
> somebody can point out to me what I did wrong.
> Regards,
> Gerald
> --
> -----------------------------------------------
> Dr. Gerald H. Ristow
> Division of Engineering
> Colorado School of Mines
> Golden, CO 80401-1887, U.S.A.
> -----------------------------------------------
Gerald,
Substitute the following lines in your scene. You will
find that objects that have a high refraction value when used
in a scene with two contrasting colors like you have here (black background/white
floor}
that glass like objects will look dark
as you noted. It really is a true representation of what you
would see but not always desirable. We can tone this down a bit
by lowering the ior refraction value down to a point were it just
turns on refraction but does not refract the background colors
overly much.
Ken Tyler
**************
// add max_trace_level 15 to your global settings line
plane { <0,.5, 0>, -9.00
pigment { color rgb <0.9, 0.9, 1.0>}
finish{ambient .4 diffuse .2}}
#declare KT_Glass6 =
texture { pigment {rgbf<.99,1,1,1,>}
finish { ambient 0.1 diffuse 0 specular 1 roughness 0.0003
phong 1 phong_size 600 reflection 0.1 brilliance 2}}
difference {
cylinder { <0, 0, 5.00>, <0, 0, -5.00>, 3.7
texture{KT_Glass6}interior{ior 1.13}}
cylinder { <0, 0, 5.01>, <0, 0, -5.01>, 3.5
texture { KT_Glass6 }interior{ior 1.13}}}
// if you are using pov 3.0x remove interior
// and put ior 1.13 in finish statement of
// KT_Glass6 above
box{<-50,0,50>,<50,50,48>
pigment{rgb 1}
finish{ambient 1}}
// added behind camera to creat white light source
// and something to reflect on the sphere surfaces.
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