POV-Ray : Newsgroups : povray.newusers : Focal point Server Time
2 Nov 2024 07:26:57 EDT (-0400)
  Focal point (Message 1 to 7 of 7)  
From: Oleguer Vilella
Subject: Focal point
Date: 19 Aug 2004 04:49:26
Message: <41246996$1@news.povray.org>
I read the focal_point and blur_samples file on the help file.
Can anyone me tell how can I calculate the focal_point?
If I have a camera and 4 differnt objects, How can I know the focal_point
the objects?

Thanks in advance,
Oleguer Vilella


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From: Warp
Subject: Re: Focal point
Date: 19 Aug 2004 05:50:53
Message: <412477fc@news.povray.org>
Oleguer Vilella <ole### [at] infonegociocom> wrote:
> I read the focal_point and blur_samples file on the help file.
> Can anyone me tell how can I calculate the focal_point?

  There's no need to calculate anything.
  The image will be sharpest at the specified focal_point (and every
point which is at the same distance from the camera as the focal_point).

  For example, if your camera is located at <1, 2, -3> and it's looking
at <0, 0, 0>, then if you specify a focal_point <0, 0, 0> the image
will be sharpest at the world origin (and every point which is at
the same distance from the camera as the world origin).

  If you have for example an object centered at <-2, -3, 4> and you
want that object to look sharp in the image, specify your focal_point
as <-2, -3, 4> (regardless of your camera location and look_at).

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -


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From: Oleguer Vilella
Subject: Re: Focal point
Date: 19 Aug 2004 06:03:43
Message: <41247aff$1@news.povray.org>
Ah, ok. That's it. All understood Warp.

Thank you,
Oleguer


news:412477fc@news.povray.org...
> Oleguer Vilella <ole### [at] infonegociocom> wrote:
> > I read the focal_point and blur_samples file on the help file.
> > Can anyone me tell how can I calculate the focal_point?
>
>   There's no need to calculate anything.
>   The image will be sharpest at the specified focal_point (and every
> point which is at the same distance from the camera as the focal_point).
>
>   For example, if your camera is located at <1, 2, -3> and it's looking
> at <0, 0, 0>, then if you specify a focal_point <0, 0, 0> the image
> will be sharpest at the world origin (and every point which is at
> the same distance from the camera as the world origin).
>
>   If you have for example an object centered at <-2, -3, 4> and you
> want that object to look sharp in the image, specify your focal_point
> as <-2, -3, 4> (regardless of your camera location and look_at).
>
> -- 
> #macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb
x]
> [1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
> -1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// -
Warp -


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From: Hughes, B 
Subject: Re: Focal point
Date: 19 Aug 2004 10:53:04
Message: <4124bed0$1@news.povray.org>
I see you are getting plenty of help here, so I won't add anything except
about what you asked me in e-mail about doubling the arrow. If I understand
right, this is very simple. One way to do it:

// double-ended arrow
union {
cone { +y, 1, +2*y, 0 } // points toward + y (pluses not needed)
cylinder { -y, +y, 0.5 } // centered on 0 y
cone { -y, 1, -2*y, 0 } // points toward - y
pigment {rgb 1}
scale 4
scale <1,2,1>
rotate <0,0,-180>
translate <200, -20, 0>
}

Replying late because of making a new car buy after my 10 year old truck's
waterpump decided to fail. Lot's of researching done to finally narrow that
down to a 2004 Subaru Impreza Outback Sport. I was going to get a small SUV
at first then happened across that car (or wagon).

Speaking of "focal point", as in the original message here, I was getting
new eyeglasses. In fact, replacing lenses of the new eyeglasses I just got
because I couldn't read very well using "progressive" lenses (for both
reading and regular seeing).
Changed to regular-only again and don't even want to try bifocals. I'll get
reading glasses someday. For now I can hold things out to read them, even
though words can be small that way. :) I don't know how people read with
those progressive things! I had about one word in focus at a time, the rest
were a blur.

Bob H.


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From: Oleguer Vilella
Subject: Re: Focal point
Date: 19 Aug 2004 13:58:52
Message: <4124ea5c@news.povray.org>
Hello Bob,

I'm glad to recibe your news. Yes, I'm getting help here in the group and
Warp and the other partners were traying to solve my questions.
About the arrow, please, can you tell me why you put a "y" in the vector?
I don't know about cars, you said a Subaru Impreza Outback Sport I think
that's a 4x4. Is it correct? I don't know what's "waterpump" I searched on
the dictionary but it doesn't appear.
Also, I wear eyeglassses, but I haven't got a progressive lenses. I have
short-sightedness, but I don't use them to read, only with the computer, the
TV...
Well, now I'm thinking to do a different background, a cloudy scene, but I
want to do it differnt than the others that I have, I'm thinking... :)

Best regards,
Oleguer Vilella



news:4124bed0$1@news.povray.org...
> I see you are getting plenty of help here, so I won't add anything except
> about what you asked me in e-mail about doubling the arrow. If I
understand
> right, this is very simple. One way to do it:
>
> // double-ended arrow
> union {
> cone { +y, 1, +2*y, 0 } // points toward + y (pluses not needed)
> cylinder { -y, +y, 0.5 } // centered on 0 y
> cone { -y, 1, -2*y, 0 } // points toward - y
> pigment {rgb 1}
> scale 4
> scale <1,2,1>
> rotate <0,0,-180>
> translate <200, -20, 0>
> }
>
> Replying late because of making a new car buy after my 10 year old truck's
> waterpump decided to fail. Lot's of researching done to finally narrow
that
> down to a 2004 Subaru Impreza Outback Sport. I was going to get a small
SUV
> at first then happened across that car (or wagon).
>
> Speaking of "focal point", as in the original message here, I was getting
> new eyeglasses. In fact, replacing lenses of the new eyeglasses I just got
> because I couldn't read very well using "progressive" lenses (for both
> reading and regular seeing).
> Changed to regular-only again and don't even want to try bifocals. I'll
get
> reading glasses someday. For now I can hold things out to read them, even
> though words can be small that way. :) I don't know how people read with
> those progressive things! I had about one word in focus at a time, the
rest
> were a blur.
>
> Bob H.
>
>


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From: Alain
Subject: Re: Focal point
Date: 19 Aug 2004 17:00:44
Message: <412514fc$1@news.povray.org>
Oleguer Vilella nous apporta ses lumieres ainsi en ce 19/08/2004 13:57... :

>Hello Bob,
>
>I'm glad to recibe your news. Yes, I'm getting help here in the group and
>Warp and the other partners were traying to solve my questions.
>About the arrow, please, can you tell me why you put a "y" in the vector?
>I don't know about cars, you said a Subaru Impreza Outback Sport I think
>that's a 4x4. Is it correct? I don't know what's "waterpump" I searched on
>the dictionary but it doesn't appear.
>  
>
Waterpump: It make the water circulate in an engine to cool it. Separate 
it in 2 words: water pump

>Also, I wear eyeglassses, but I haven't got a progressive lenses. I have
>short-sightedness, but I don't use them to read, only with the computer, the
>TV...
>Well, now I'm thinking to do a different background, a cloudy scene, but I
>want to do it differnt than the others that I have, I'm thinking... :)
>
>Best regards,
>Oleguer Vilella
>
>

>news:4124bed0$1@news.povray.org...
>  
>
>
>>right, this is very simple. One way to do it:
>>
>>// double-ended arrow
>>union {
>>cone { +y, 1, +2*y, 0 } // points toward + y (pluses not needed)
>>cylinder { -y, +y, 0.5 } // centered on 0 y
>>cone { -y, 1, -2*y, 0 } // points toward - y
>>pigment {rgb 1}
>>scale 4
>>scale <1,2,1>
>>rotate <0,0,-180>
>>translate <200, -20, 0>
>>}
>>    
>>
The "y" can be used as a shorthand for: <0,1,0>
In this case, it make your arrow vertical around the y axis, centered at 
the origin.

Alain


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From: Oleguer Vilella
Subject: Re: Focal point
Date: 20 Aug 2004 03:16:59
Message: <4125a56b$1@news.povray.org>
Ok, Alain. Thank you very much,


news:412514fc$1@news.povray.org...
> Oleguer Vilella nous apporta ses lumieres ainsi en ce 19/08/2004 13:57...
:
>
> >Hello Bob,
> >
> >I'm glad to recibe your news. Yes, I'm getting help here in the group and
> >Warp and the other partners were traying to solve my questions.
> >About the arrow, please, can you tell me why you put a "y" in the vector?
> >I don't know about cars, you said a Subaru Impreza Outback Sport I think
> >that's a 4x4. Is it correct? I don't know what's "waterpump" I searched
on
> >the dictionary but it doesn't appear.
> >
> >
> Waterpump: It make the water circulate in an engine to cool it. Separate
> it in 2 words: water pump
>
> >Also, I wear eyeglassses, but I haven't got a progressive lenses. I have
> >short-sightedness, but I don't use them to read, only with the computer,
the
> >TV...
> >Well, now I'm thinking to do a different background, a cloudy scene, but
I
> >want to do it differnt than the others that I have, I'm thinking... :)
> >
> >Best regards,
> >Oleguer Vilella
> >
> >

> >news:4124bed0$1@news.povray.org...
> >
> >
> >
> >>right, this is very simple. One way to do it:
> >>
> >>// double-ended arrow
> >>union {
> >>cone { +y, 1, +2*y, 0 } // points toward + y (pluses not needed)
> >>cylinder { -y, +y, 0.5 } // centered on 0 y
> >>cone { -y, 1, -2*y, 0 } // points toward - y
> >>pigment {rgb 1}
> >>scale 4
> >>scale <1,2,1>
> >>rotate <0,0,-180>
> >>translate <200, -20, 0>
> >>}
> >>
> >>
> The "y" can be used as a shorthand for: <0,1,0>
> In this case, it make your arrow vertical around the y axis, centered at
> the origin.
>
> Alain


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