I would try eroding the motion vectors a pixel or two less than your color and alpha, then comping it back in using a smaller and slightly blurred alpha.
Hope that helps. Ryan On Jul 6, 2012 3:25 AM, "Joe Laude" <[email protected]> wrote: > Off the top of my head, first thing I'd check is if your vector channel is > antialiased and getting unpremulted somewhere. That could give you really > high values along the edges where it's getting divided by the alpha. > > Joe Laude > Sent from my iPhone > > On Jul 5, 2012, at 11:05 PM, Jordan Olson <[email protected]> wrote: > > > Hey guys! > > I'm compositing a CG character at the moment with DOF (using depth > > channel) and also plugging in motion vectors into a nuke Vector Blur > > node. As I'm applying DOF first, (relatively soft)- I like to expand > > the motion vector channels outside the character's initial alpha using > > an erode (both in positive and negative space). This usually works > > fine for us, but THIS time I'm getting a really strange spikey > > artifact. Clamping has no effect on it. > > > > Now I've attached an image (100kb), not sure if it'll stay attached to > > this email through the mailing list, but it's a screenshot of the > > issue in question. > > If I toggle the erode/expand gizmo I have on the motion vectors, > > turning it off does solve the spikey issue, but then I'm back to > > square one! I need to expand the motion vectors and this has always > > worked before. > > > > Any ideas what could be causing the vector blur to freak out on the > > alpha edges and give random spikey anomalies? > > cheers, > > Jordan > > <vectorblur_artifact.jpg> > > _______________________________________________ > > Nuke-users mailing list > > [email protected], http://forums.thefoundry.co.uk/ > > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users > _______________________________________________ > Nuke-users mailing list > [email protected], http://forums.thefoundry.co.uk/ > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >
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