include objects behind glass with alpha channel (HELP PLEASE)

[scostumatu]

Hi all

 

I was wondering how one would include objects in the alpha channel behind vray glass? For example, Im doing an interior scene and the view consists of a living room shot with a balcony in view. The balcony consists of some furniture along with a railing fence (luckily) - now the alpha channel only includes just the glass and not the object behind it - i want to add a backdrop in post by also retaining the objects behind the glass.

Ive obviously set the glass to affect shadows and ive included all the channels in 'affect channels.

any help would be much appreciated.

[jasonstewart]

Try affect Color + Alpha. I had the opposite issue a while back and selecting all channels was the fix. I think that will do what you want.

[scostumatu]

Thanks for the reply Jason - but that didnt seem to work either :\

 

Try affect Color + Alpha. I had the opposite issue a while back and selecting all channels was the fix. I think that will do what you want.

[Zdravko Barisic]

Can you use VrayMtlID or VrayObjId as render elements for that purpose?

...

Just make Mtl/Obj ID unique, and add render element, also make use AA in render elemetns settings.

[Corey Beaulieu]

Try affect Color + Alpha. I had the opposite issue a while back and selecting all channels was the fix. I think that will do what you want.

 

the only differenc I have ever seen between Color+Alpha and All Channels is that All Channels includes the render elements which causes the refraction and reflection passes to no longer work in a linear sense. When compositing theses passes in PS, you will see an overbright result. It has only been a problem when trying to build a beauty pass from the elements rather than using the final image.

[scostumatu]

thanks for the assist guys - still cant figure it out - its racking my brain as ive seen it done before... arrgghh

[mavinova]

I have the same problem right now. Cant figure it out. Because in other scenes and projects I didnt have this problem.

 

The objects behind the glass is absent in alpha channel. Alpha channel renders like the glass has nothing behind. just black.