POV-Ray : Newsgroups : povray.newusers : Another question on co-ordinates and space Server Time
14 Nov 2024 06:16:13 EST (-0500)
  Another question on co-ordinates and space (Message 1 to 3 of 3)  
From: I Chuprov
Subject: Another question on co-ordinates and space
Date: 30 Mar 1999 04:00:55
Message: <37009286.8510D5A1@tig.com.au>
Ok, say I set up a scene, and place the camera at <0, 0, -30> and look_at is set
to <0,0,0>

How many units are across the "screen" (so to speak)?
If I put something at <-30,0,0>, will it be on the far left of the screen?

Thanks,
Igor
--
Hinki's Place
http://hinki.8m.com/
Wild Planet
http://wildplanet.8m.com/
Fractalography
http://fractalography.8m.com/


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From: Bob Hughes
Subject: Re: Another question on co-ordinates and space
Date: 30 Mar 1999 09:19:21
Message: <3700DD4C.9F5028A8@aol.com>
What I know of it (which isn't much) is, if you have a camera at -10*z
looking at the origin (<0,0,0>) using 'angle' 22.6 you get 4 POV units
wide by 3 POV units high approximately.
And if using 'direction' instead of angle for the "lens zoom" setting
you would need 'direction' 10/3 (ten divided by 3) to approximate a
'angle' 22.6  (the old POV-Ray camera default).
So 'direction' 10/3 is about the same area as angle 22.6.
In your example to get that -30*x object to show at the far left when
the camera is located at -30*z would require 'angle 90' or so. A very
wide lens setting. Keep in mind this is the default 'perspective'
camera.
Anyhow, dividing 30 by 10 (distance) you get 3 times the area. These
aren't exact numbers at all remember, only close.
Hope this is a start of help about this.

I Chuprov wrote:
> 
> Ok, say I set up a scene, and place the camera at <0, 0, -30> and look_at is set
> to <0,0,0>
> 
> How many units are across the "screen" (so to speak)?
> If I put something at <-30,0,0>, will it be on the far left of the screen?
> 
> Thanks,
> Igor
> --
> Hinki's Place
> http://hinki.8m.com/
> Wild Planet
> http://wildplanet.8m.com/
> Fractalography
> http://fractalography.8m.com/

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto:inv### [at] aolcom?Subject=PoV-News


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From: Josh English
Subject: Re: Another question on co-ordinates and space
Date: 30 Mar 1999 18:54:32
Message: <3701649C.8414888E@spiritone.com>
If your camera angle is at 90, then yes, an object  at <-30,0,0> will be at the very
left edge of the window.
If you use an angle of 60, then the left edge will be at
tan(angle/2)*distancefromlocationtolook_at or -17.3205in this case.

Josh English
eng### [at] spiritonecom

I Chuprov wrote:

> Ok, say I set up a scene, and place the camera at <0, 0, -30> and look_at is set
> to <0,0,0>
>
> How many units are across the "screen" (so to speak)?
> If I put something at <-30,0,0>, will it be on the far left of the screen?
>
> Thanks,
> Igor
> --
> Hinki's Place
> http://hinki.8m.com/
> Wild Planet
> http://wildplanet.8m.com/
> Fractalography
> http://fractalography.8m.com/


Post a reply to this message

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