CGTalk - Timewarp Effect Techniques

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MF3dream

10-23-2009, 01:21 PM

Hello, I'm just curious about how timewarp effects are applied to films and specially animations...
For example we know that for an animation there is a lot of effects going on like cloth simulations... particle effects etc plus the actual character animations.
currently most compositing programs offer some types of timewarp nodes or operators that whether interpolating the frames or simply extending the time of the clips... but I want to know, are these methods are qualitative? and do the major companies implementing almost the same techniques or what?
I heard from someone that they extend/contract the frame per second (fps) in actual 3d applications because of reaching to full control and quality specially in animations, but I think beside of probable quality in results (because all things are done in rendering and not post process), this makes the entire pipeline somewhat complicated for those like animators or effect artists for example! they have to work in high fps in their 3d applications.
So how we should approach the timewarp for having quality? (if there is any lose or a better way to do that)
Thanks in advance

RogerWickes

11-03-2009, 04:20 AM

I'm not quite sure I understand your question, but I can answer for Blender and other NLE Sequencers feature a Speed Control that can speed up or slow down the delivered frame rate of a video. When you speed up, you are mostly just dropping out frames and pulling ahead. When slowing down, it get a little tricky because you have to "make up" frames for the middle, so if you slow down too much, you can get jerky (or blurry if you let the computer average the frames). For that reason, if the DP knows they are filming a shot that will in post-pro get slowed down, they film that shot at a higher frame rate, so that there are more frames available for smooth motion when it is slowed down.

MF3dream

11-03-2009, 03:10 PM

Thanks "RogerWickes"...
Yes for films the DP has the ability to shoot in higher frame rate when they know that they want to slow down the clip in post....
But more importantly how we do that in an animation sequence?!
Animating in higher FPS in the actual 3d program or
Animating at normal fps (24fps for example) and slowing down the entire sequence in post, And if we do it that way, then it comes tricky as you said, creating new frames between the original ones.

sundialsvc4

11-04-2009, 01:19 AM

Well of course, "there are several ways to do it." You can certainly generate CG frames and then process them "in post" just as you would do with live-action or model-based footage. (An added advantage of CG techniques is that you can selectively render parts, or layers, of material for subsequent compositing.)

As with anything else, you'd probably start with: "what visual effect visually says 'time warp' to me?"

Then you put on your managerial hat and say: "that sounds cool, so how can we do that in one-fourth the time you say it will, and still wind up with something that sux only slightly?" :thumbsup:

And thus you "come up with a strategy." And you do it, and maybe you wince a little bit and console yourself that "no, it really doesn't sux that bad..." and in time you realize that no, it really doesn't sux after all. It conveys the idea, it looks good (enuf...), and you got it done on-time.

MF3dream

11-04-2009, 03:42 AM

got it...
there may be tons of ways to do this of course, and looks like extending the fps in
3d application is practical too...
thanks "sundialsvc4"

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