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
> --
>
>
>

Post a reply to this message