"Rich" <SrP### [at] ricoswebcom> wrote in message
news:Xns### [at] 204213191226...
> "Chris B" <c_b### [at] btconnectcom> wrote in
> news:3fdf2f74@news.povray.org:
>
> > If you know the targetLocation before you translate the object and the
> > object is defined at the origin, then you can rotate it before moving
> > it. If you only need to rotate around the Y axis then the angle is the
> > arctan in degrees of z / x. So you can use atan2d():
> >
> > #declare targetLocation = <3,4,5>;
> > #declare targetAngle = atan2d(targetLocation.z,targetLocation.x);
> >
> > Hope I understood your question correctly.
>
> I think you do understand my question, but when I use your formula I
> don't get the expected results.  I've output the relevant variable values
> and copied them below.  Only one or two of these objects are actually
> pointing at or nearly at the origin...
>
> #declare rotation = atan2d(z1,x1);
> #object {
>   thing
>   rotate <0,rotation,0>
>   translate <x1,y1,z1>
> }
>
>
> Z:  0.1,  X:  3.5,  Rotation:   1.0
> Z:  1.4,  X:  3.0,  Rotation:  25.0
> Z:  2.3,  X:  2.0,  Rotation:  49.0
> Z:  2.7,  X:  0.8,  Rotation:  73.0
> Z:  2.5,  X: -0.3,  Rotation:  97.0
> Z:  2.0,  X: -1.2,  Rotation: 121.0
> Z:  1.2,  X: -1.7,  Rotation: 145.0
> Z:  0.4,  X: -1.8,  Rotation: 169.0
> Z: -0.4,  X: -1.6,  Rotation:-167.0
> Z: -0.8,  X: -1.1,  Rotation:-143.0
> Z: -1.0,  X: -0.6,  Rotation:-119.0
> Z: -0.9,  X: -0.1,  Rotation: -95.0
> Z: -0.7,  X:  0.2,  Rotation: -71.0
> Z: -0.3,  X:  0.3,  Rotation: -47.0
> Z: -0.1,  X:  0.2,  Rotation: -23.0

The initial axis in the Reorient macro is the initial direction your object
is pointing.  Assuming that your object is created to point in the +z
direction, this should work:

#object {
    thing
    Reorient( z, <-x1, -y1, -z1> )
    translate <x1, y1, z1>
}

I hope this was helpful.

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