Hi,
is it possible to shift the Camera horenzotally  (incl. look at point)
from the current point of view, in order to render two pics (one for the
left and on for the right eye), or do i have to calculate the right
position 3-dimensionally?

Bob

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Well a persons eyes are just along side each other so it's really just a
horizontal shift.  Not much either unless the scene is intended to be very
close.  Of course if not sticking to realism entirely then you could still have
a large shift.  I've taken photos that way in order to see large scale objects
in 3D.
I've also just rotated the camera around the y axis a bit without even using a
translate for 'location' or 'look_at' and it doesn't seem to make too great a
difference.  If only approximation to a stereo image is all you want then that
could be okay but you'd probably need the look_at point set out beyond the
central focus of your scene.

Bob


news:38EDF2D6.2F0E915F@exmail.de...
| Hi,
| is it possible to shift the Camera horenzotally  (incl. look at point)
| from the current point of view, in order to render two pics (one for the
| left and on for the right eye), or do i have to calculate the right
| position 3-dimensionally?
|
| Bob
|

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many thanks for your tip, Bob,
i tried it out and it works well, but in a close up view it is not the right way, i
think. i really want to make "close up`s".

is there really no way to shift the camera horizontally in an easy way?

Bob

Bob Hughes schrieb:

> Well a persons eyes are just along side each other so it's really just a
> horizontal shift.  Not much either unless the scene is intended to be very
> close.  Of course if not sticking to realism entirely then you could still have
> a large shift.  I've taken photos that way in order to see large scale objects
> in 3D.
> I've also just rotated the camera around the y axis a bit without even using a
> translate for 'location' or 'look_at' and it doesn't seem to make too great a
> difference.  If only approximation to a stereo image is all you want then that
> could be okay but you'd probably need the look_at point set out beyond the
> central focus of your scene.
>
> Bob
>

> news:38EDF2D6.2F0E915F@exmail.de...
> | Hi,
> | is it possible to shift the Camera horenzotally  (incl. look at point)
> | from the current point of view, in order to render two pics (one for the
> | left and on for the right eye), or do i have to calculate the right
> | position 3-dimensionally?
> |
> | Bob
> |

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For close proximity you'd most likely want to shift both left and right from a
central spot.  As simple as adding and then subtracting a number from the x
value in the camera location and look_at vectors.
The average human eyes are separated by about 2 and a quarter inches I think it
is, so a 1.125 inch shift for each ought to do okay if you apply that to the
scale of your scene.
There are differing ways of doing the stereo pair; some say to look past the
"focus" so that location/look_at have same change, and others say to have a
focal (not the best word for it) point where the look_at remains fixed and only
the camera location moves.
Keith Rule, author of the Crossroads 3D file format convertor, has something
written up about stereo-pairs: http://www.povray.org/povzine/povzine2/3d.html

Bob

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: is it possible to shift the Camera horenzotally  (incl. look at point)

  If you think about it, the eyes are like two cameras. The locations of
the eyes are at your face. The look_ats of the eyes are at the point you
are looking at (for example right now the surface of the monitor).
  Thus, to create a 2-eye image you should define their look_ats to be at
the desired focal point where the "virtual" viewer is looking at.
  If you just shift the cameras it would be like you were looking at the
infinity.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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> is there really no way to shift the camera horizontally in an easy way?
What is horizontal? You can press Ctrl-Alt and the left-click-drag in
the 3D view, moving the mouse horizontally only. This will shift the
camera parallel to the viewing plane. 

I've found that I leave the lookat unmoved for stereo pairs. I set the
lookat for the place that is supposed to be the center of focus and
then only move the location. That's how the eyes work, isn't it?

- Lutz
  email : lut### [at] stmuccom
  Web   : http://www.stmuc.com/moray

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> : is it possible to shift the Camera horenzotally  (incl. look at point)
>
>   If you think about it, the eyes are like two cameras. The locations of
> the eyes are at your face. The look_ats of the eyes are at the point you
> are looking at (for example right now the surface of the monitor).
>   Thus, to create a 2-eye image you should define their look_ats to be at
> the desired focal point where the "virtual" viewer is looking at.
>   If you just shift the cameras it would be like you were looking at the
> infinity.

Hmm ... you're all talking about, what may be the better way for stereopics:
shift both, camera AND lookat or just the camera.

I find, that it doesn't play a big role which option you select. The problem
of may be looking into infinity,or to close on your 'focal-point' is IMHO
solved when overlaying the 2 pics to view them. If you don't shift the
lookat with the cam, you maybe have to shift them closer together (the right
one more to the left and vice versa). then you should have the same
impression, of course not on the borders of the image.

I think the question is how you want to view the pics.

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Lutz Kretzschmar schrieb:


>
> > is there really no way to shift the camera horizontally in an easy way?
> What is horizontal? You can press Ctrl-Alt and the left-click-drag in
> the 3D view, moving the mouse horizontally only. This will shift the
> camera parallel to the viewing plane.

Many, many thanks Lutz,
that is, what i wanted to know.

Bob

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