Motion Blur with Velocity channel

[jonnybefree]

hi again,
anybody an idea if its possible to use the velocity-channel in After effects for gettin right MB?
I've tried it several times without success, but i think combustion is able to do it, so AE?

Best regards
Jonas

[RErender]

From what I have seen it will work for a whole object like a ball flying through the scene but if it is for a part of an object it will not work if it passes infront of itself.

[jonnybefree]

hi rerender,
the mail-notification works
we're working actually on a fly wich is crossing the screen very fast several times. without MB the average rendertime is 30 sec., with MB up to 1h!!.
i think its a good opportunity to bring in the V-channel.
did you tried it allready by yourself? and in case, how?
thanks
jonas

[Morbid Angel]

I have exported a velocity channel inside an RPF. You will need to check options like coverege and velosity. It takes a bit of experementing but it works and its quite good.
However RPF wont read through AE, as I believe there is no option for RPF blur in it. But there is in combustion. In AE instead you can get a plugin called RSMB - Reel Smart Motion Blur, which works on several principals: one being velicity vector from 3d such as what mental ray exports from lamaison shader, (there is a built in shader in max 8 for that) two it tried to calculate frame before and after a current frame and blur it on that, however that is gimpy because in some cases it doesnt work (for example when an object is outside of the screen it wont know how to blur it when it enters into screen)
So my suggestion is try RPF if you can, if not try lm2d (lamaison) in rsmb.
engoy

[jonnybefree]

hi dmitry,
thanks for the tip,
i allready try'd rsmb, without too much success. like you said, the fly is too fast, and sometimes out of view, so it doesn't work for that.
i'm on the way to install combustion. its the first contact, but maybe it'll help.
best greetings
jonas

[mike.edel]

you might want to read
http://www.revisionfx.com/generalfaqsMVFrom3D.htm
and especially
http://www.revisionfx.com/generalfaqsMV3DSMax.htm

a bit complicated as every version of max requires a different method

[jonnybefree]

hi mike.edel,
yes thanks i allready saw it, but it isn't very convincing.
i've tried it with combustion now, and it works great as .rpf with velocitiy MB.

[panthon]

Don't you find rpf motion blur noisy and sometimes inexact, artifacts here and there?

[tom schuelke]

Well as jonas and me found out, those looong rendertimes on some of the frames seem to be a bug.


it seems to be gone in newer builds and to get reduced to much much much better rendertimes..... 1,5 hours to 3 minutes



tom

[panthon]

Well as jonas and me found out, those looong rendertimes on some of the frames seem to be a bug.


it seems to be gone in newer builds and to get reduced to much much much better rendertimes..... 1,5 hours to 3 minutes



tom

[mike.edel]

according to the rsmb site fast movement should be ok if you use 16bit or floating point accuracy for your motion vectors

regarding the fly going off-screen:

BONUS: Keith Chamberlain from Discreet provides the following tip. If you have portions of your animation coming on and/or off screen you will probably want to render a larger image than ultimately needed, then process with our plugin, then crop using your favorite compositing package. You can find the overscan script here: http://www.breidt.net/scripts/, and scroll until you find the overscan script.

shouldnt be slower if you just render the fly without the background

[jonnybefree]

the main problem comes with the wings.
i think there are 20 wing beats a second or something like this.
i think there isn't a post-mb wich can handle this.