Dear Alain and Christian

Thank you very much for your response and giving me suggestions to read the text
file.
I am able to produce the image, but still i have got some issues

I use camera location and look_at and light_source with these positions given
below.

Actually i used different positions for them to get a nice 3-dimensional image,
but i think i am not using optimal values

the set of particles positions i have, x-position ranges from 0.0 to 40.0;
y-position ranges from 0.0-20.0 and z-position ranges from 0-10.0

that means x-dimension is of 40 particle diameter length; y-dimension is of
20-particle diameter length and z-dimension is of 10-particle diameter length

particle diameter is 1.0

could you please suggest me the best way to put the light source and camera
position


background { color Cyan}
camera {
    location <0, 5, -3>
    look_at  <24, 9, 2>
}
light_source { <10, 5, -3> color White}



thanking you
anki








lain <aze### [at] qwertyorg> wrote:

> > Hi  Alain and Simon
> >
> > Thanks a lot for your reply, atleast some things are clear now
> >
> > actually my text file looks like below
> > 1st column is sphere number
> > 2nd column is x-position, 3rd- y position and 4th- z -position
> > there are 4000 particles in a box
> >
> > 1 487.726807 383.565125 99.485672
> > 2 377.206238 393.352325 17.296064
> > 3 452.328613 346.985321 33.054535
> > 4 453.301697 334.173981 14.480576
> > 5 724.187988 389.938171 55.237068
> > 6 298.778717 388.706055 30.780521
> > 7 685.588074 366.411072 31.322350
> > ...............................
> > .........................
> > ...........................
> > 4000 56.78   456.67   234.56
> >
> >
> > i can make the text file , where columns are separated by commas like
> >
> > x1,y1,z1
> > x2,y2,z2
> > x3,y3,z3
> > ......
> > ......
> >
> > still i have a doubt about the format to use in *.pov file to read this text
> > file
> >
> > is it like to put the commands as
> >
> > "#fopen identifier 'pos.txt' read
> > while loop
> > end"    in a file named sphere.pov and use ./povray sphere.pov to produce
> > rendering image ?
> >
> > could you please suggest me a sample *.pov file which reads a text file
> > containing the positions of particles like i have
> >
> > thank you very much
> > regards
> > anki
> >
>
> Put a coma after each values.
>
> Sample file:
>
> #declare Cluster = union{
>   #fopen DATA_FILE "pos.txt" read
>   #read(DATA_FILE, PosX, PosY, PosZ)
>    #while (defined(DATA_FILE))
>    sphere{<PosX, PosY, PosZ>, Radius}
>    #end
>    #fclose DATA_FILE
>    pigment{rgb 1}
>    }
>
> It opens your input file and read the first 3 values.
> It then start a loop.
> The loop place a single sphere, then it reads the next 3 values.
>
> It will continue to loop until you reatch the end of your file. At that
> moment, DATA_FILE becomes undefined and the loop falls through.
> The #fclose DATA_FILE is not realy needed as the file is automaticaly
> closed, and it's identifier suppressed, after you tried to read past
> it's end.
> After the end of the loop, a texture is applied to the union and the
> union is closed.
>
> I used a #declare. It allows you to use your cluster of spheres several
> times with no need to read your data a second time.
>
> This construction allows you to read any file of any length with no need
> to know how many elements are contained in it.
> You don't need any array.
>
> You can use any object as your shape, you are not limited to use spheres.
>
>
> Alain

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