I think what he was getting at was that once you do a zdefocus, your object edges do not match your motion vectors. And vice versa (motion blurring your Z depth)
I have had to fake this by extending my mv edges out for objects effected by DOF. As far as I know, there is no way to do this, and if it's going to have artifacts, we just render in 3d. R On Dec 27, 2013 12:49 PM, "Andy Jones" <[email protected]> wrote: > I'm assuming the crux of the question is about how to do both zblur and > motion blur as a single operation. I don't know of a way to do that OOTB. > You could presumably write a plugin that tries to do both together, but it > would likely be pretty slow when dealing with large movements, since there > are a lot of original pixels that could potentially influence each output > pixel. It would still probably be worth doing. I think I may have heard > that Blender had something kind of like this, but I can't say first hand. > > The other way I've approached it in the past is to either do DOF first, > and then use Oflow for motion blur, or, if the motion is more or less > continuous across the image, to do DOF first and use the vectors, taking > care to ensure that the blurriness of the edges doesn't mess anything up. > You may need to defocus or dilate the motion vectors premultiplied, and > then unpremultiply them. > > One thing to keep in mind is that, as useful as they are, 2D Motion Blur > and 2D depth of field are both artifact-prone in certain situations. So > even if there were a plugin to do them simultaneously, the result wouldn't > always be perfect. In many cases, when you hit a problem scenario, the > best bet is just 3D motion blur and/or 3D DOF. This is one reason I try to > avoid workflows that depend on sharp non-blurred content when comping cg. > It's very annoying to have to go back and reinvent the wheel or > counter-correct all the edge artifacts when you need to apply your comp to > motion blurred 3D. Or worse, to be told that 3D motion blur isn't an > option because it won't work with the comp. > > 2D motion blur in particular really breaks down when it comes to dealing > with shiny objects. Good evidence of this is the spinning wheel rim on a > car. In real life, criss-crossing specular highlights go all over the > place in a really beautiful way. > > Don't get me wrong, though -- I still use 2D Motion blur and DOF all the > time. > > > On Thu, Dec 26, 2013 at 2:44 PM, Richard Bobo <[email protected]> wrote: > >> As far as order of operation goes, I did my camera/object motion blur >> operation first, z-depth second. In my mind, I see the motion blur as a >> property of the scene you’re capturing - and the depth as a function of the >> device - the camera iris, sensor and lens - doing the capturing. That’s >> probably an arbitrary distinction, but it seemed to work the way I wanted >> it to. I could adjust how long the motion blur streaks were - essentially >> the shutter or exposure, if you will - and then determine how much depth of >> field I wanted and where the focal point needed to be. Also, downstream, I >> had other camera effects, such as lens distortion, chromatic aberration, >> highlight glow, lens barrel vignette and grain/noise. >> >> Rich >> >> >> >> >> On Dec 26, 2013, at 2:25 PM, Joe Laude <[email protected]> wrote: >> >> I know the exact problem you're talking about, and it probably depends a >> lot on the situation. The last time I ran into this situation, I think I >> did DOF first, then MB. >> >> I'd say the one that's going to be the most extreme, you should do >> second. Little motion, shallow DOF, do MB first then DOF; and vice versa, >> if there's more deep DOF, and more MB, do DOF first, then MB. If they're >> both extreme, try both and see which looks better. Might just need to >> finesse some parts. >> >> Sent from my iPhone >> >> On Dec 26, 2013, at 12:41, Gary Jaeger <[email protected]> wrote: >> >> I know it’s a common question, but I’m curious if there are any tricks to >> do both in post? >> >> Gary Jaeger // Core Studio >> 249 Princeton Avenue >> Half Moon Bay, CA 94019 >> 650 728 7060 >> http://corestudio.com >> >> _______________________________________________ >> 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 >
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