"Thomas de Groot" <t.d### [at] internlnet> wrote:
> I changed your little scene a bit, just to make it more intuitive for me.
> I don't know what happens, but it has to do imo with the relative, combined
> positions of camera, media sphere, and spotlight. I don't think that the
> spotlight code itself is the culprit. Try this with the scene below, only
> switching the camera z-position between -70 (no aberration) and -80
> (aberration in one of the spheres).
>
> Thomas
>

Hi, Thomas, sorry for the delay in answering (it has been  *busy* two days
for me.)

Thanks for posting your code.  I put a looks_like sphere into your
spotlight., then took a look at the scene from the top. Alain is right
about the positioning of the media spheres, they're both "behind" the
location of the light, outside the cone.  BUT, you're also right, in that
one of the spheres DOES show the aberration if the camera is moved back
slightly...due to that sphere now falling between the camera and the light
cone. Which points up how difficult it is to actually *produce* this effect
on purpose--the camera/media sphere/light all have to be in a particular
alignment to show the effect.  Which is probably why I had never noticed
this behavior before (or if I did, I never made the connection between all
three items.) Pretty crazy, huh.

Ken

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