"zachrahan" <nomail@nomail> wrote:
> I'm trying to figure out a way to get some objects to always "point" at the
> camera, no matter where I move it. (Imagine an array of solar mirrors
> mounted on gimbals so that they always point at the sun.)
>
> Anyhow, I can see two ways I might do this in povray:
>
> (1) If there were some way I could obtain the camera-to-world transform
> (that is, the inverse of the world-to-camera transform, unless I've gotten
> the two backwards) and apply that to objects in the scene, then this would
> have the effect of "undoing" any camera motion so the objects always
> "point" at the camera in the same orientation.

Yes there is, but I don't have time to explain now. Sorry.
(Hopefully someone else will have time to explain.)


> (2) If there were some way to specify the orientation of objects via
> "lookat" and "sky" parameters, as you can with the camera, I could just set
> the camera and the objects to look at each other, with a common sky vector.
>
> Option 2 is neat because it's more general -- you could have objects all
> point at any arbitrary thing. However, I don't see anything like that in
> the documentation, so I assume that it's probably option 1 or nothing?

I'm not sure what you mean, but you might find some answers in my replies in
this thread:

http://news.povray.org/povray.advanced-users/thread/%3Cweb.43022440433cdf6544365ed70%40news.povray.org%3E/

From: Mike C
Subject: "Point at a vector; angles for rotation on axes X and Y /w nonzero
origin"
Date: 16 Aug 2005

--
Tor Olav
http://subcube.com

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