Uh-hah. Could someone give me an example of how to use the vnormalize()
function? The POV 3.1 docs aren't too clear on that.

--
 camera{location<0,0.25,-2> look_at 0.5*y} #declare
T=texture{pigment{crackle scale 0.5 rotate 90 turbulence 0.75 color_map{[0
rgb 1][0.05 rgb 1][0.1 rgb<1,0.25,1>][0.25 rgbf 1][1 rgbf 1]}}
finish{ambient 1}} #declare c=difference{torus{0.5,0.1
rotate -90*x}box{<0.7,0,0.2>,<-0.7,-0.7,-0.2>}}  merge{object{c
translate<0.5,0.5,0>} object{c translate<-0.5,0.5,0>}
cylinder{<1,0.5,0>,<1,0,0>,0.1} cylinder{<-1,0.5,0>,<-1,0,0>,0.1}
cylinder{0.5*y,0,0.1} texture{T}}
//Mahalis
--


"Wilson Reis" <wil### [at] ismcombr> wrote in message
news:3bc87e5c@news.povray.org...
> Do that same thing with a cylinder that starts in <0,0,0> and goes to x .
> (or y or z, of course).
>
> When you manage to do it with your cylin, you can be sure it will work
with
> the sphere as well, when the cylinder's edge can be the starting place for
> the iris of the eye you've been working on.
>
> First thing is to normalize the look_at vector , and figure out the
> necessary transformations to reach it. Spherical coordinates (teta and
phi)
> will help, i presume.
>
> Hope i've helped
> Will
> PS: We should thank Jacobi as well.
>
>
>
>
> "Mahalis" <don### [at] fakeycom> escreveu na mensagem
> news:3bc87a94@news.povray.org...
> > How would I rotate a sphere so that a certain point on the sphere would
> > point at location<x,y,z>?
> >
> > --
> >  camera{location<0,0.25,-2> look_at 0.5*y} #declare
> > T=texture{pigment{crackle scale 0.5 rotate 90 turbulence 0.75
color_map{[0
> > rgb 1][0.05 rgb 1][0.1 rgb<1,0.25,1>][0.25 rgbf 1][1 rgbf 1]}}
> > finish{ambient 1}} #declare c=difference{torus{0.5,0.1
> > rotate -90*x}box{<0.7,0,0.2>,<-0.7,-0.7,-0.2>}}  merge{object{c
> > translate<0.5,0.5,0>} object{c translate<-0.5,0.5,0>}
> > cylinder{<1,0.5,0>,<1,0,0>,0.1} cylinder{<-1,0.5,0>,<-1,0,0>,0.1}
> > cylinder{0.5*y,0,0.1} texture{T}}
> > file://Mahalis
> > --
> >
> >
> >
>
>
>
>
>
>

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