3 Replies Latest reply on Sep 18, 2009 5:39 PM by Miha Kokalj

    Motion blur options?

    Miha Kokalj
      Hello!

      I'm working on a new project. Footage is being recorded from a game at 300 fps (then resampled to 30). I'd like to achieve the same motion blur as for footage take with a normal camera. I tried a few things but I'd like to see if there are some other options:

      Shrani.si

      Plain frame blending from framerate resampling from 300 to 30.

      Shrani.si

      Reel Smart Motion Blur plug-in without frame blend switch on. Looks pretty decent at first sight and renders reasonably fast. But under closer inspection it shows a lot of incorrect interpolation at a lot of elements.

      Shrani.si

      Reel Smart Motion Blur plug-in with frame blending switch on. Similar to the previous example.

      Shrani.si

      CC Force Motion Blur plug-in with interpolation switch on. Produces a great result at a cost of really long render times. Also i have no idea where to set the shutter phase (native shutter and interpolating dont work together?).

      Are there any other options?

      Thanks a bunch.
        • 1. Re: Motion blur options?
          craulmedia Level 1
          adobe help suggests for example:

          > To achieve a result similar to the result of ReelSmart Motion Blur, apply the Timewarp effect, set Speed to 100, enable motion blur within the effect, and use the manual shutter control features to adjust the motion blur.

          since CS3 the comp MB settings are enhanced, try to experiment with different settings. an example of what Chris Meyer is suggesting:

          Shutter Angle: 360
          Shutter Phase: -180 (always use minus-half value of shutter angle)
          Samples pre frame: 64 (maximum value)
          Adaptive Sample Limit: 256

          increase/decrease at your own taste or if you have problems rendering heavy MB.
          • 2. Re: Motion blur options?
            Mylenium Most Valuable Participant
            For RSMB, you will possibly have to tweak the vectors using Twixtor. Naturally, faking 3D motion blur from 2D info must not yield the correct result. As for the rest - all of what you see is logical. Frame blending with an even quotient will always sample smack to the discrete frame falling on that increment, so essentially the amount of blending samples is equal to the quotient. There's no way around that. You could just do it in multiple steps to get more samples, i.e. first reduce to half, then quarter etc., not at once. CC Force Motionblur employs a similar scheme - stretching out frames in time and request additional samples inbetween, then accumulate them. Since it resorts to AE's internal functions, it's just as slow. An alternative would be to use SK Frame Accumulate from RevisionFX SmoothKit. It uses a smarter method and thus is considerably faster.

            Mylenium
            • 3. Re: Motion blur options?
              Miha Kokalj Level 1

              Hey guys,

               

              its been a while and Im playing around with motion blur of high fps footage again.

               

              I've tried the effect CC Wide Time which blends a designated number of frames before and after the current frame.

              I have footage recorded at 1000 fps. In comparison frame mix would blend 40 frames into a single frame (1000 fps to 25 fps) which would represent a shutter angle of 180° (i believe). That doesn't look smooth enough in my mind, so in CC Wide Time i set the values to 80 frames total (39 ahead, 40 behind, 1 current just to be accurate ), which represents the shutter angle of 360° with a phase of -180°.

               

              Now the problem is that i would like to time remap the clip. After a precomp i time stretch the clip to obtain the real life time scale - 1000 fps to 25 fps, with the motion blur i describe above. If i enable time remap and start playing with slowmotion the intensity of motion blur intesity (blurred frames) stays the same, which isnt right. A way to fix that would be to use a linear 40 -> 0 frames blended corresponding to the velocity achieved by timeremaping, but i cant seem to find a way to use clip velocity in expressions.

               

              I could use timewarp and use speed value instead of time remap, but that seems like a pain especially when i think of applying ease to the keyframes.

               

              To think all of this could be avoided if CC Force Motion Blur would offer shutter phase.

               

              Any thoughts on the issue?

               

              Thanks!