"Slime" <fak### [at] emailaddress> wrote:
> You can simply use atan2( vect.y, vect.x ). Note that this is equivalent to
> atan( vect.y / vect.x ) but avoids the problem of division by zero.
>
> This will give you the angle in radians. If you want it in degrees, use
> degrees( atan2( vect.y, vect.x ) ).
>
>  - Slime
>  [ http://www.slimeland.com/ ]


yep... much better. I had no idea how to make that, THANKS!! but... here's the
problem I've been trying to avoid:

#include "colors.inc"
#include "math.inc"

#declare vect = <-1,1,0>;

camera{
  location <0, 0, -10>
  look_at 0
  angle 30
}

light_source{ <2,20,-20> White }

sphere { 0 .025 pigment { rgb <0,0,1> }} // ORIGIN
sphere { vect .025 pigment { rgb <1,0,0> }}


box { <-.25,0,-.25>, .25 pigment { rgb .5}
    scale <.25,1,.25>
    rotate <0,0,degrees( atan2( vect.y, vect.x ) )>
    }

depending on the quadrant where the vector is the box will point the wrong way.
Couldn't figure out an easy solution for this. Any ideas? Thanks again!

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