Out of interest if you remove the zblur and erode set up is it good?
Howard
>________________________________
> From: Jordan Olson <[email protected]>
>To: Nuke user discussion <[email protected]>
>Sent: Saturday, 7 July 2012, 4:38
>Subject: Re: [Nuke-users] vector blur spikey artifacts on the alpha channel?
>
>thanks Guys,
>thing is- viewing the motion vector layers (positive and negative
>space) and checking the values with my values indicates it's all
>normal- no extreme values as we're seeing. It really seems like a bug
>or a glitch. I'm a comp TD and have been working with Nuke for a few
>years, so I can say that with a fair degree of certainty.
>No unpremult operations happening on the motion vectors- only a two
>stage erode setup.
>I'll keep trying different things to see what I can do.
>
>cheers,
>Jordan
>
>On Sat, Jul 7, 2012 at 12:56 AM, Ryan O'Phelan <[email protected]> wrote:
>> 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
>>
>>
>> _______________________________________________
>> 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
>
>
>
_______________________________________________
Nuke-users mailing list
[email protected], http://forums.thefoundry.co.uk/
http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
