Compositing Problem with Vray SphereFade

[re:FORM]

I'm trying to follow the tutorial explaining how to use the vray spherefade gizmo for compositing rendering animated objects.

I'm using after effects for compositing and I'm not sure how to translate the "subtract" and "divide" modes.

I came across this post in another thread but it still doesnt help

It's simple:

DIVIDE OPERATOR:

C= A/B,

right?

you hav e aDIVIDE operator in gimp, but not in PS

In PS or AE the equivalent is:

C = 1-B/A

where DIVIDE is Color dodge

so

1-B = Invert

and

C = 1-B/A = Color Dodge

you have a DIVIDE operator in PS (or AE).

Can you help me get the workflow in that tuturial to work in AE?

[re:FORM]

Also, because I am rendering through glass, the grey that you specify in the atmospheric effect is not rendering as mid-grey. Even removing the glass does not cause vray to render the areas outside the sphere as grey.
Have I hit some over-rides elsewhere which affect the colour of the "empty color"?

[re:FORM]

Ok. I've managed to get it working(just!) in after effects. There's a workaround to achieving a "divide" operation in AE. For those that are interested you can find the details here : http://finthrow.blogspot.com/2007/03...-after.htmlOne problem I have though, is that my "black" layer seems to be receiving some lighting which results in my composited people doing an interesting "invisible man" impression
Is there a way to make a vraylight material completely black? I've tried using a material wrapper to remove the black material from the GI solution but it still gets shaded by the lighting.
I know I can explude the characters from the lights, but that's not the most convenient solution. If there's a way to get a clean black render without doing this I would love to hear it.

Thanks!

[re:FORM]

AH! I found the problem...Looks like my sphere gizmo was too close to the character so was starting the alpha falloff.

Doh!

[stevesideas]

Enjoy speaking to yourself do you ??


Good to know that though. Will check out that method..ive had to use masks before to comp in spherefade renders..bit of a bodge job, but i didnt know how else to do it...

[mcnamex]

sweet find