POV-Ray : Newsgroups : povray.newusers : a given camera doesn't give expected object's shadow laying direction : Re: a given camera doesn't give expected object's shadow laying direction Server Time
25 Sep 2021 14:45:46 EDT (-0400)
  Re: a given camera doesn't give expected object's shadow laying direction  
From: clipka
Date: 25 Sep 2018 16:55:43
Message: <5baaa0cf@news.povray.org>
Am 25.09.2018 um 19:55 schrieb Warren:

> camera{
>  orthographic
>  location <0, 4, 0>
>  look_at 0
>  sky z
>  up 4*z
>  right 4*x
> }
...

> Ps: from my point of view, the above camera settings (without the 'direction'
> line) should make a camera without any mistaking for povray , I mean povray
> shouldn't need to append default settings because it has everything it needs to
> make the render ?
> Thank you.

Without the `direction`, POV-Ray has no idea whether you want a
left-handed or right-handed coordinate system.

Remember, the `look_at` mechanism works as follows:

(1) POV-Ray first sets up the camera as specified by your `up`, `right`
and `direction` vectors, as if the `look_at` statement wasn't there.
This defines the handedness of the coordinate system, the aspect ratio,
and (depending on camera projection) the zoom (unless you also specify
`angle`).

(2) Once that is done, POV-Ray re-orients the camera (rotating it around
its location) in such a manner that the `look_at` point is in the center
of the image (for most projections at any rate).

So specifying `look_at` is no replacement for specifying `direction`.


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