I agree with Chris. Do your key without any premultiplication then you can merge your animated mask in as stencil to cut out the parts that you don't want anymore.
On Wed, Mar 16, 2011 at 5:40 PM, chris <[email protected]> wrote: > hmm, i'm not a specialist with IBK, but generally i try to > avoid premultiplication of a matte before the key as it can > introduce dark edges around the mask. > > try to first pull the key, then use a Merge(min) to combine > the (inverted) garbage matte alpha with the key alpha, then > do your premults if necessary. > > obviously there are quite a few other ways depending on how > you like to work which will give you the same results.. > > ++ chris > > > On 3/16/11 at 12:42 AM, [email protected] (Manuel > > Gonzalez) wrote: > > Hi all, >> >> >> I am battling with the worst greenscreens shoots ever. In order to >> minimize all the awesome junk around the actor we have an animated garbage >> matte that is premult before feeding into the IBK. The result of the IBK >> gives a nice key. In the alpha of the IBK, inside the garbage mask I have >> the nice key, outside is white. My question is, how to make the outside of >> that alpha black ?. Plate>Garbage Matte>Premult>IBK Colour>IBK Gizmo. I >> can merge the plate back and do an inside, using the animated garbage matte >> as the holdout matte. The thing that is confusing me is that, when I >> premult the plate, in the alpha the outside is already black(0), shouldn't >> the IBK just pass that value along and give that result plus the inside of >> the animated garbage matte ?. >> >> >> >> Thanks, >> >> >> > _______________________________________________ > Nuke-users mailing list > [email protected] > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users > -- Nick Guth motion . composite . design www.nickguth.com
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