adding a background behind a window

[salf]

Ok, adding a background in PS is easy, I just either save my file in MAx as .png or Targa, so I wont have the background.

 

But heres the thing, im doing a interior scene, wher ethe cam looks to the outside, through a huge glass window, actually a curtain wall, so I cant use the same trick because I want to keep the reflections on the window, that meanst I render with the glass, so I cannot separate the max background in some alpha channel.

 

ANy ideas on how to tackle this sorta thing?

 

Im guessing Im stuck with adding the background I want in 3d MAX, but the colors are way off, so I was wondering if there were some tricks in photoshop for this.

[edub]

try playing with the layer modes (multiply, overlay, etc.) Your best bet is probably if you can get a white background behind the window without washing out the reflections.

[Exellite]

when you save as a tiff or something that can store alphas it stores the reflections as well, they just show up as less transparent on the alpha channel.

[AlNe]

Use inverted Alpha channel for a background mask and "Screen" blending mode for it.

[Guest nazcaLine]

if you are using vray, then when creating a glass there is an option in the refraction section called "affect alpha" (or something like that). if you check it, you'll be able to keep the reflections and alpha. good luck

 

Eduardo