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maximee
01-06-2006, 05:12 PM
Hi everyone -

I'm currently 2D-animating a music clip.

My main character has rotoscoped outlines at 12 fps. The outlines are layered over an organic paper structure. The character and the background both have their own color and structure.
I have a shadow plate for my character (generated by using the threshold level filter) which I use as an alpha matte.


Now what I want:

I want the characters shadows not to be totally black, I want them to have some sort of photocopied/stamped structure. The problem is: the structure needs to move accordingly with the character.

How would I achieve that?

I tried tracking the shadows to each moving body part. But that's way too time-consuming.

I also tried to make the static structure less recognizable by applying various quite complicated animated noise patterns. But all of them looked either very synthethic/digital or just flickered like hell, even at 12 fps.

I had some luck with the tinderbox t_etch demo but the look is not right, I want the photocopy-look, not ink and pencil or crayon.
The cool thing about t_etch is that it has a "seed with pixel" option that makes the cross-hatch structure move with the optical pixel flow.
I think this is what I need. I need some sort of plugin/workflow that lets me apply optical flow data to a texture which then moves accordingly.

I know PFtrack has an optical flow system, but how would I use the data gained from PFtrack in AfterEffects?

Does all of that make sense?
Or has anybody a different approach to this topic?
Any help is very much appreciated!

Cheers!
Flo

ratbaggy
01-06-2006, 10:36 PM
I don't really understand what the problem is. care to post again? or with diagrams/screengrabs?

:)

maximee
01-06-2006, 11:03 PM
Hi ratbaggy!

Ok...I read my previous post again and I must admit that it must seem quite confusing to you :) Sry about that.

Alright, here is a quick screenshot:
http://www.europeantranslation.de/notwist/notwist_screenshot1.jpg

The problem is the area of the shadow marked by the red arrow.

When the head moves the structure does not because it is one layer below.
That's basically it.

What I want is the structure moving seperatly with the hair, the area around the right eye, the shoulder, the lips and so on. A couple of simple 2D tracks in AE would work here. But that's not an option for me here, later in the movie I have TONS of things flying around in different directions, crossing each other and so on. That would be a total mask-painting nightmare.

What would you suggest?

Thanks for your time and patience!
Flo

ratbaggy
01-06-2006, 11:10 PM
Flo,

If Iu nderstand correctly - When you say "shadow" you mean the entire dark area of the hair etc. is that right? (so ... that's on a diff layer because you want to add more texture to the dark areas)

I'm thinking it's going to have to be done with mattes and pre/sub comps

Looks like a really nice treatment by the way.

:)

maximee
01-07-2006, 12:56 AM
Hey Paul!

I'm happy you like what you saw!!! Thanks.


With "shadow" I mean the dark areas. I generated them by applying the threshold level filter.

I uploaded another screenshot of the main comp timeline to make things more clear:

http://www.europeantranslation.de/notwist/notwist_screenshot3.jpg


(so ... that's on a diff layer because you want to add more texture to the dark areas)

I do not want to add more texture to the dark areas. The dark areas it self do not have any textures at all, they are generated from the original video footage. I applied the threshold level filter to make the dark areas 100% black. That way I can use the layer called "shadow matte" as a luma matte for my background called "photocopy texture".

This texture is a still image.

What I'm trying to achieve is that the "photocopy texture" layer somehow moves when the head/the shoulders/the lips move.
As I said, tracking multiple masked instances of the texture layer to each seperate part of the character's body would work. But my team and I are really in a hurry, I just don't have time to seperately mask and track hundreds of moving tentacles. (Yes. Tentacles. Hundreds of them. :) ) We already have to draw about 3000 frames by hand...

My idea was that there must be some sort of tool to analyze the pixel movement frame by frame and apply this gained information to a texture and warp/translate it according to the optical pixel flow.
PFTrack for example does optical flow analysis. But I have no clue how to use the flow data on a texture.

I only know that you would use flow data for applying realistic motion blur to moving objects...but that's not what I want to do here...

Are you still with me? :)

Thanks a bunch!!!
Flo

Mylenium
01-07-2006, 11:44 AM
Hey Paul!

I'm happy you like what you saw!!! Thanks.


With "shadow" I mean the dark areas. I generated them by applying the threshold level filter.

I uploaded another screenshot of the main comp timeline to make things more clear:

http://www.europeantranslation.de/notwist/notwist_screenshot3.jpg




I do not want to add more texture to the dark areas. The dark areas it self do not have any textures at all, they are generated from the original video footage. I applied the threshold level filter to make the dark areas 100% black. That way I can use the layer called "shadow matte" as a luma matte for my background called "photocopy texture".

This texture is a still image.

What I'm trying to achieve is that the "photocopy texture" layer somehow moves when the head/the shoulders/the lips move.
As I said, tracking multiple masked instances of the texture layer to each seperate part of the character's body would work. But my team and I are really in a hurry, I just don't have time to seperately mask and track hundreds of moving tentacles. (Yes. Tentacles. Hundreds of them. :) ) We already have to draw about 3000 frames by hand...

My idea was that there must be some sort of tool to analyze the pixel movement frame by frame and apply this gained information to a texture and warp/translate it according to the optical pixel flow.
PFTrack for example does optical flow analysis. But I have no clue how to use the flow data on a texture.

I only know that you would use flow data for applying realistic motion blur to moving objects...but that's not what I want to do here...

Are you still with me? :)

Thanks a bunch!!!
Flo

There is no plugin that can use vector/ optical flow data in the manner you describe (it would take forever to generate it in PFTrack, anyway). The problem simply is that there is no real movement and whatever alternative techniques (like expressions) could be used.

Have you tried using the displacement effect instead of actually moving your layer with the shadow structure? If you already have extracted the shadow areas, it should be simple to use them for this. The only problem is that you still need to animate the amount of displacement in realtion to how fast things move. I'm afraid you have to face the hard truth that some manual adjustments/ tracking cannot be avoided.

The only other thing I could think of is creating a grid of color sampler effects (which require third party plugins) and than create some extremely complex expressions to derive a simple linear motion vector from frame to frame. It's going to be a major task and may take too long for you to finish in time.

Mylenium

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