[Papervision3D] Camera FoV

[Peter Kapelyan]

Hi

I was saying to consider the fact since ZOOM basically moves the camera
closer - perhaps you can look at what ZOOM does in the code, but my feeling
is that it simply just moves the camera closer - and focus accounts for the
"fish eye" etc.

If you figure out that ZOOM may just be the same as bringing the camera
close - maybe that will help you figure it out?

-Pete

On 6/12/07, Marcelo Caetano Martins Muniz <marcelo at ciestudios.com> wrote:
>
>  If you use DirectX for example, the FoV has a big rule in the camera
> Zoom.
> Generally people use 45 as diagonal FoV, but if you change from 45 to 25
> the object will look closer.
>
> Check the attached images, both images the camera is at the same distance
> from the object, the only difference is the Field of View.
>
>
>
> When I use papervision, if I just change the camera focus the objects
> won't look any closer. I see the projection difference but no zoom
> difference.
>
>
>
> So, I think that if I want to synchronize DirectX or OpenGL camera with
> Papervision3D I'll have to change both focus and zoom. And that's why I'm
> after a formula that gets as input the scene stage size and diagonal field
> of view and return the papervision focus and zoom.
>
>
>
> Does it make sense to you?
>
>
>
> Thanks,
>
> Marcelo Muniz
>
>
>  ------------------------------
>
> *From:* Papervision3D-bounces at osflash.org [mailto:
> Papervision3D-bounces at osflash.org] *On Behalf Of *Peter Kapelyan
> *Sent:* terça-feira, 12 de junho de 2007 21:54
> *To:* Papervision3D at osflash.org
> *Subject:* Re: [Papervision3D] Camera FoV
>
>
>
> Hi, I seriously DOUBT it because it is not truley 3d...however I am sure
> it comes very close.
> Also I realize you maybe have answered your own question! I don't think
> zoom will help you because I believe it in effect the same as moving the
> camera closer to the focal point, so it almost seems like zoom might not
> play a part in your scenario unless maybe you convert it to a Z position?
> Just an idea.
> -Pete
>
>
>
> On 6/12/07, *Marcelo Caetano Martins Muniz* <marcelo at ciestudios.com>
> wrote:
>
> I can't give you a code example but I'll give you the scenario.
>
>
>
> I have renderers implemented in Directx and OpenGL that output renders
> (images) to me.
>
> In these renderers I can set any value as diagonal field of view to the
> camera.
>
>
>
> What I wanna do is to use a low poly version of my 3d models in
> papervision, so the user can set the camera position in the scene, click on
> a button to render and I output an image of the same scene rendered using
> high poly 3d models on my renderers.
>
>
>
> The default diagonal FoV that I use in the renderers is 25. The flash
> stage and the output image have the same size 622x310. I could synchronize
> the papervision camera with my renderers using the following formula to find
> the papervision camera focus:
>
> var diagonalFOV:Number = 25;
> var width:Number = 622;
> var height:Number = 310;
> var w:Number = width;
> var h:Number = height;
> var d:Number = Math.SQRT((w * w) + (h * h)) ;
> var focalDistance:Number = d * Math.TAN(diagonalFOV / 2.0) ;
>
> And I had to manually adjust the papervision camera zoom until it matches
> the rendered images.
>
>
>
> I have the following questions:
>
> 1) Does the papervision camera focus represent the focal distance that we
> find in any standard 3D game library (DirectX/OpenGL) for camera settings?
> 2) How can I calculate automatically the papervision camera focus and zoom
> if I give you as input my stage size and diagonal field of view?
>
> Thank you,
>
> Marcelo Muniz
>  ------------------------------
>
> *From:* Papervision3D-bounces at osflash.org [mailto:Papervision3D-bounces at osflash.org]
> *On Behalf Of *Peter Kapelyan
> *Sent:* terça-feira, 12 de junho de 2007 20:57
>
>
> *To:* Papervision3D at osflash.org
> *Subject:* Re: [Papervision3D] Camera FoV
>
>
>
> Ok I am back - can you send me any code (hopefully flex as3 or cs3)?
> I will try to give you a good answer!
> -Pete
>
>
>
> On 6/12/07, *Marcelo Caetano Martins Muniz* < marcelo at ciestudios.com>
> wrote:
>
> Ok. I'll be waiting for you response.
>
>
>  ------------------------------
>
> *From:* Papervision3D-bounces at osflash.org [mailto:Papervision3D-bounces at osflash.org]
> *On Behalf Of *Peter Kapelyan
> *Sent:* terça-feira, 12 de junho de 2007 15:30
> *To:* Papervision3D at osflash.org
> *Subject:* Re: [Papervision3D] Camera FoV
>
>
>
> Hi someone posted a calculator or something (my suggestion). I will look
> tonight - literally out the door now.
> -Pete
>
>
>
> On 6/12/07, *Marcelo Caetano Martins Muniz* < marcelo at ciestudios.com>
> wrote:
>
> Hi,
>
>
>
> I still got no answer about how to calculate the camera Field of View
> using focus and zoom.
>
>
>
> I did some research and I find out how to calculate focalDistance, is it
> the same as the camera focus?
>
> Here is formula I found how to convert diagonalFOV to focalDistance.
>
>
> var diagonalFOV:Number = 25;
>
> var width:Number = 622;
>
> var height:Number = 310;
>
> var w:Number = width  ;
>
> var h:Number = height  ;
>
> var d:Number = Math.SQRT((w * w) + (h * h)) ;
>
> var focalDistance:Number = d * Math.TAN(diagonalFOV / 2.0) ;
>
>
>
> If focalDistance is the same as the camera focus, it still doesn't make
> sense how to calculate the correct camera zoom for one selected FoV.
>
> Does anyone have some clue to this puzzle?
>
>
>
> Thanks,
>
> Marcelo Muniz
>
>
>
>
>
>
>
>
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