Hi Dean,
basically it's all because of anti aliasing. Connecting two renders that
are supposed to fit together by using multiplication (an Over operation,
for example) will not result in a perfect connection and you will see a
little black line between them (see attached example which will explain
this way better than how I wrote it).
The way to fix this is to use either a Plus operation or a Disjoint-over
operation. If you look at the math of this you can see exactly why. By
multiplying that edge again when doing the Over operation you are
contracting the edge further and that results in an edge.
This won't help your predicament, though. What you have is the car and then
the shadow cut out of the car. The white halo was simply that same black
line from the example. Usually I ask for the shadow renders to be rendered
without them being cut out from the object. That way I don't have these
edges. If anybody has any better ideas I would love to hear them.

Hope this helped.

(on a computer with no Nuke license, hence the .nkple file).




Ron Ganbar
email: [email protected]
tel: +44 (0)7968 007 309 [UK]
     +972 (0)54 255 9765 [Israel]
url: http://ronganbar.wordpress.com/



On 1 June 2012 16:22, yaw3d <[email protected]> wrote:

> **
> Hey guys thanks for all the tips. i have tried everything but nothing
> works. But i managed to solve the problem by coping the alpha into the raw
> shadow pass and added a CC node after with the offset option set to 1.
>
> If anyone can spare some time and explaining why this problem occurs and
> best way of using vray shadow passes in NUKE. Im quite new to vray. so not
> sure what im doing wrong.
>
> Thanks dean
>
>
> ------------------------------
>
> www.yaw3d.co.uk
>
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Attachment: example.nkple
Description: Binary data

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