POV-Ray : Newsgroups : povray.general : Render a Mask ? : Re: Render a Mask ? Server Time
3 Aug 2024 12:17:52 EDT (-0400)
  Re: Render a Mask ?  
From: Tek
Date: 29 Feb 2004 22:59:55
Message: <4042b53b$1@news.povray.org>
> My question is: wasn't there talk of some feature, a long
> time ago, about rendering a "mask" from a scene?

Well you can use the +ua command line switch to get pov to output an alpha
channel (so that your background will be transparent).

> The interesting part, that I need some help with, is dealing
> with the shadows.  Assuming I put my object into a scene
> that has props for the real objects the shadows will fall
> on, how can I copy those in Photoshop to darken the photo?

What I would suggest is render a second image with all the textures set to pure
white, and all the finishes set to have brilliance 0. This should mean you end
up with a flat white image where only the areas in shadow are darker (it won't
cope well with coloured lights but you can probably get round that with some
tweaking in photoshop).

Then, put that into photoshop and make it multiply the colours in your
photograph (it has to multiply because that's what shadows do).

That should get the effect you're after.

-- 
Tek
www.evilsuperbrain.com


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