Jittery animation

[barad_dur]

I am getting some really wierd jitter in my animations in Houdini 10. I never noticed it before but I took a simple animation and ran it all the way through the pipeline to compositing and at every stage I get this jitter in the output.

I am wondering if I am just not setting something up that is very apparant and simple say like "sub-frame rendering" or something. I know this is just something simple that I am missing and just need a swift kick in the pants to get it cleared up.

I am attaching the .hipnc. Any help would be appreciated. It is just a sphere moving along the X-Axis from X=-8 to X=8 over the course or 24 frames. I have this same animation at 48, 128 and 256 frames all at 24 FPS. All of them seem to have an issue but the one I am attaching is the worst.

Thanks

David

[barad_dur]

Hmmm . . . The file didn't attach. Me try again then go play with fire.

Ball_Test_24.hipnc

[Mario Marengo]

Looks fine to me.

The playback "jitter" is simply reflecting the fact that the sphere, at the beginning of a given frame, is in a different position than at the beginning of the next/previous frame, and if this difference is big enough (because the sphere is moving fast), then it will appear to "jump" from one position to the next as you scrub. However, the intermediate positions are still there and are smoothly interpolated -- you're just no seeing them because you're moving in intervals of a whole frame.

So...

For playback "smoothness", you can open up the global playback options (right-most icon on the play bar) and toggle "Integer Frame Values" off.

And for rendered smoothness, you need to add motion blur (MantraROP > Sampling > Allow Motion Blur).

HTH.

[barad_dur]

I thought as much. The integer checkbox did the trick in the scene view. However, I just rendered the sequence out and pumped it through Premier Pro (CS4) into an AVI that I have attached here. I am still getting jitter and I am thinking now that it is because the sphere is traveling too far of a distance over the course of 24 frames in order for the sequence to be anything but jittery.

If this is indeed the case then that leads to the inevitable question, "is there a rule of thumb to go by that describes the maximum amount of translation that an object can undergo at X FPS?"

Ball_Test_24Frames_0001.avi

[majikal]

i think your problem is not houdini. in your video you got 28 frame. How many did you render in houdini for this sequence? your video file is 29,97 FPS.

The video is also interlaced. Did you render interlaced frames ( i doubt that). You got some bad pulldown going on in there.

Check if your houdini FPS, premiere imoported footage FPS, premiere timeline FPS and output avi FPS match.

I suggest that you work in progressive mode all the time. Go with interlacin only for old almost obolete tv standard if you know what you are doing.

Edited January 25, 2010 by majikal

[barad_dur]

Yeah, I know it's not Houdini. This is definitely user buffoonery. I have been so obsessed with all these other aspects of Houdini and learning so much that I forgot to pay attention to getting stuff out! With that said, however, even when I run these frames in mplay I still get the whole jitter thing. Now the one thing I haven't done is play the video on another computer but my video driver is up to date though and I have enough memory.