Vray Light Dome Invisible background color

[stupendousman_dk]

Hi

I am currently trying to render out a bunch of layers thats needs to be composited later on. I render all my objects seperatly using mattes on my background (which is rendered seperatly). Now when i composite these together, I get a nasty edge on my objects.

I use a Vray Light as Dome with HDRI. Therefore I use invisible to have the HDRI not show up in my rendered files. BUT here's the question: When my light is set to invisible the background color turns black. Can I somehow make this turn white instead? I believe that will fix my compositing problems

Thanks in advance

[mike_kennedy]

What Compositing Program are you using? If it supports premultipied alpha you can sample the color and it should clean up the edges.
Cheers
Mike K

[stupendousman_dk]

I am using Flash CS3 in a XML solution where I can dynamicly swap objects. Flash only support multiplieing with the solor WHITE it seems. And i am rendering out in PNG's.
A workaround might be to save as floating point data, remove the background via Alpha and substitude the background with a white color - then save as a 8-bit PNG maybe.

If I could some how sample the PNG easily in Photoshop it could help me out, like an Action in PS.

hmm

[RErender]

Changing the max environment color to white does not work? Maybe i am missing something

[stupendousman_dk]

No it does not work, when using domelight+hdri it either becomes the color of the texture or, if set to invisible, black.

[joa_grilo]

Its kind of easy to resolve this.

put your enviroment to white in max

in vray dome light untick afect reflections,
then in vray enviroment put yours hdri image in the
reflection/refraction enviroment override.

Done

Its the same thing as having your normal dome light with hdr plus having a blacj background for composite.

[stupendousman_dk]

If I do that, I wont get any importance sampling... The light will just become all white. But you are right about the white background. But that is just the color of the domelight though.

Example attached

[RErender]

Hmm, I can't see what I am missing

in Max 9 / vray sp2, if I create a dome light, set it to invisible, add a hdri and set the max environment to a color that color is the background. What is the difference I am missing?

[stupendousman_dk]

The importance sampling, look at posted images.

[dlparisi]

If I understand what you want to do correctly, just follow Eric's direction but check the vray environment override and set it to black.