Render overscan?

[Steve Davy]

Is there a simple way to keep camera focal length but render an overscan?

I've seen a few "tips" online about how to do this but a few tests seem to show they either result in a scaled render (i.e. pixels are blurry), or the focal length changes which is exactly what I want to avoid.

Is there a simple way to just render additional pixels that are outside of the existing camera's gate, while maintaining focal length?

Maybe there's a script that will do this?

[Angel Ivanov]

You can do:

cameraScale * overscanFactor

renderResolution (X,Y) * overscanFractor

[Steve Davy]

Can you elaborate a bit?

Is overscanFactor a camera attribute? Can't see it anywhere.

Unless you're referring simply to Overscan, but multing that by render resolution will simply give you higher image resolution.

Camera scale appears to change focal length, which is what I want to avoid...

Thanks.

---

Date: Fri, 24 Jun 2011 00:36:17 +0300
Subject: Re: [maya_he3d] Render overscan?
From: lunat...@gmail.com
To: maya...@googlegroups.com

[Angel Ivanov]

Sorry for being incomplete. The overscanFactor is how much over the normal you would like to render.

Say you want 25% more, then you'll have:

cameraScale * 1.25

renderResolution (X,Y) * 1.25

Regarding cameraScale: I don't think it's changing the focal length. If you crop the overscan render to the normal resolution you should get the same image.

[Kym Watts]

this is the mel i used to used to overscan the camera, it was reverse
engineered from some code i saw in 3dsmax.

snip-->
string $selCams[] = `ls -sl`;

float $percent = 0;
float $hozFilmApp = `getAttr ($selCams[0]+".horizontalFilmAperture")`;
float $vertFilmApp = `getAttr ($selCams[0]+".verticalFilmAperture")`;
float $xRes = `getAttr "defaultResolution.width"`;
float $yRes = `getAttr "defaultResolution.height"`;

setAttr ($selCams[0]+".horizontalFilmAperture") ($hozFilmApp+
($hozFilmApp*$percent));
setAttr ($selCams[0]+".verticalFilmAperture") ($vertFilmApp+
($vertFilmApp*$percent));

setAttr "defaultResolution.width" ($xRes+($xRes*$percent));
setAttr "defaultResolution.height" ($yRes+($yRes*$percent));
<--snip

I havent used this code for a number of years, so i hope it helps.

On Jun 24, 2:13 am, Angel Ivanov <lunatika...@gmail.com> wrote:
> Sorry for being incomplete. The overscanFactor is how much over the normal
> you would like to render.
> Say you want 25% more, then you'll have:
> cameraScale * 1.25
> renderResolution (X,Y) * 1.25
> Regarding cameraScale: I don't think it's changing the focal length. If you
> crop the overscan render to the normal resolution you should get the same
> image.
>
>
>
>
>
>
>
> On Fri, Jun 24, 2011 at 12:50 AM, Steve Davy <stevied...@hotmail.com> wrote:
> >  Can you elaborate a bit?
>
> > Is overscanFactor a camera attribute? Can't see it anywhere.
>
> > Unless you're referring simply to Overscan, but multing that by render
> > resolution will simply give you higher image resolution.
>
> > Camera scale appears to change focal length, which is what I want to
> > avoid...
>
> > Thanks.
>

> > ------------------------------

> > Date: Fri, 24 Jun 2011 00:36:17 +0300
> > Subject: Re: [maya_he3d] Render overscan?

> > From: lunatika...@gmail.com

> > To: maya...@googlegroups.com
>
> > You can do:
> > cameraScale * overscanFactor
> > renderResolution (X,Y) * overscanFractor
>

[Steve Davy]

Ah, no that was me being dense... ;)

UR right -- it appears to introduce a lot of lens distortion in the viewport but it doesn't affect focal length. However I notice how much blurring seems to result in the "good pixels" when the scale is bumped up to 2. Generally I avoid using any kind of scaling on cameras -- it can cause all sorts of problems with bump mapping, motion vectors etc. I'm wondering if the scale attr has the same issues....

---

Date: Fri, 24 Jun 2011 09:13:34 +0300

[Steve Davy]

So, this just multiplies the horizontal and vertical film apertures, and the render resolution, by whatever value you give to $percent, right? This seems to have a similar effect to using the scale attribute.

Anyone got any idea if there is any advantage to one way versus the other? Or are they the same, in effect?

> Date: Fri, 24 Jun 2011 15:11:34 -0700
> Subject: [maya_he3d] Re: Render overscan?
> From: watt...@gmail.com
> To: maya...@googlegroups.com

[stephenkmann]

i was just looking at an attribute on the camera called  "shake" and "shake overscan"

from what I can tell, it is the same as changing the film back as well as the camera scale.
so it would seem that you could change the shake overscan to your desired amount of overscan, and then increase your output resolution accordingly.


in the end, they all sort of look the same to me...

-=s

--
stephe...@gmail.com
http://smannimation.blogspot.com/
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