"Warp" <war### [at] tagpovrayorg> wrote in message
news:3cd123bb@news.povray.org...
> Antti Arola <aar### [at] lutfi> wrote:
> > AFAIK there is no other way than cropping the output.
>
>   It should be possible by shearing the camera in the exact same way as
> shearing the box in:
> http://enphilistor.users4.50megs.com/matrix.htm

Thanks! I'll look into that and tell you how it goes :)

Corey

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Corey Woodworth wrote:

> Yeah Cropping the output occurred to me, but the image I'm planning will
> probably take a good deal of time to render so I was hoping I could avoid
> rendering extra lines.


You don't have to render the parts you don't need.

You can start and end the render at the rows and columns you need. 

Look up General Output Options in the help file.


/Ib

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What you are trying to do is very similar to the long discussion
of creating a stereo camera by shearing. Both involve using
shearing to accomplish cropping that could be done in
post processing. (see the Stereoscopy thread above).

Harold

"Corey Woodworth" <cdw### [at] mpinetnet> wrote in message
news:3cd14940$1@news.povray.org...
>
> "Warp" <war### [at] tagpovrayorg> wrote in message
> news:3cd123bb@news.povray.org...
> > Antti Arola <aar### [at] lutfi> wrote:
> > > AFAIK there is no other way than cropping the output.
> >
> >   It should be possible by shearing the camera in the exact same way as
> > shearing the box in:
> > http://enphilistor.users4.50megs.com/matrix.htm
>
> Thanks! I'll look into that and tell you how it goes :)
>
> Corey
>
>

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Thanks Ib, that could be useful in rendering stereo pairs too.

Harold

"Ib Rasmussen" <thi### [at] myemailaddress> wrote in message
news:3CD### [at] myemailaddress...
> Corey Woodworth wrote:
>
> > Yeah Cropping the output occurred to me, but the image I'm planning will
> > probably take a good deal of time to render so I was hoping I could
avoid
> > rendering extra lines.
>
>
> You don't have to render the parts you don't need.
>
> You can start and end the render at the rows and columns you need.
>
> Look up General Output Options in the help file.
>
>
> /Ib
>

Post a reply to this message

Corey Woodworth wrote:

>> You don't actually set the vanishing point in POV.  Instead, the camera
>> points in a direction such that the camera points from the "location"
>> vector to the "look_at" vector.
> 
> You're misunderstanding me. I don't want to change the actual look_at
> vector because my camera is looking where I want it. I want to move the
> location of the look_at vector in the output file. In other words I have
> the look_at vector where I want it in 3D space, but I don't have it where
> I want it in 2D space.

I really think that you're misunderstanding POV.  The look_at vector is 
precisely that - the point that the camera looks at.  Now, if you want the 
object the camera is looking at to be not in the center of the picture, 
then whatever *was* in the center of the picture would be the new look_at.

For example, say we have this:

/---------------\
|       |       |
|       |       |
|       |       |
|-------X-------|
|       |       |
|       |       |
|       |       |
\---------------/

Now, let's say we want to move the X to here:

/---------------\
|    |          |
|----X----------|
|    |          |
|    |          |
|    |          |
|    |          |
|    |          |
\---------------/

look_at should no longer point at X, because the camera is looking below and 
to the right of X.  Then, the new look_at would be O:

/---------------\
|    |  :       |
|----X----------|
|    |  :       |
|::::|::O:::::::|
|    |  :       |
|    |  :       |
|    |  :       |
\---------------/

This is what you want, right?  Then, make your look_at O, not X.

Hope this made sense :)

...Chambers

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> /---------------\
> |    |  :       |
> |----X----------|
> |    |  :       |
> |::::|::O:::::::|
> |    |  :       |
> |    |  :       |
> |    |  :       |
> \---------------/
>
> This is what you want, right?  Then, make your look_at O, not X.
>
> Hope this made sense :)

Thats what I want but I want to keep the vanishing point on X. like this:

 /---------------\
 |   \|/         |
 |----X----------|
 |   /|\         |
 |  / | \        |
 | /  |  \       |
 |/   |   \      |
 |    |    \     |
 \---------------/

kinda :)

Corey

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> You don't have to render the parts you don't need.
>
> You can start and end the render at the rows and columns you need.
>
> Look up General Output Options in the help file.

Oh, wow! Didn't even think of that, Thats a great idea!

Corey

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> Thats what I want but I want to keep the vanishing point on X.

Well, technically, the vanishing point *will* stay on X just by moving the
camera or look_at vector. However, if you don't want to actually distort the
scene, that is, if you only want to sort of translate the view along the
viewing window that you have, then you have to do a matrix transformation as
others have said.

Perhaps a simple example scene would help us illustrate the concepts.

- Slime
[ http://www.slimeland.com/ ]
[ http://www.slimeland.com/images/ ]

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Unfortunately, the area not rendered is filled with black, so you
still have to edit the file in post processing. :-(

HB

"Harold Baize" <bai### [at] itsaucsfedu> wrote in message
news:3cd18818@news.povray.org...
> Thanks Ib, that could be useful in rendering stereo pairs too.
>
> Harold
>
> "Ib Rasmussen" <thi### [at] myemailaddress> wrote in message
> news:3CD### [at] myemailaddress...
> > Corey Woodworth wrote:
> >
> > > Yeah Cropping the output occurred to me, but the image I'm planning
will
> > > probably take a good deal of time to render so I was hoping I could
> avoid
> > > rendering extra lines.
> >
> >
> > You don't have to render the parts you don't need.
> >
> > You can start and end the render at the rows and columns you need.
> >
> > Look up General Output Options in the help file.
> >
> >
> > /Ib
> >
>
>

Post a reply to this message

3cd6dd45$4@news.povray.org...
> Unfortunately, the area not rendered is filled with black, so you
> still have to edit the file in post processing. :-(
>
Just cropping is not a big edition, is it? :-)
Marc

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