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rotobrush workflow

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Victor Camacho Guerrerorotobrush workflow
by on Mar 20, 2014 at 2:31:08 pm

Hello everyone,

I have been struggling with this for a while, I havent found a perfect answer, to get the perfect workflow for Rotobrush.

I would like to know your opinion if I am right or not.

1) I start with a big brush to select my foreground object to create my Base frame.

2) I keep doing small brushes to get all details.

3) I skip 3 or 5 frames and I change my propagations settings and I use the favor predicted edges or current edges depending the best result.

4) If I have to add more strokes I do it in another Span

5) I create a new span everytime the key pose of the object change considerably.

Not sure if this is the best way to go or not.

Please let me know your input.

Many thanks!


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Todd KoprivaRe: rotobrush workflow
by on Mar 20, 2014 at 3:19:17 pm

> I skip 3 or 5 frames and...


Go frame by frame.

Corrective strokes only apply outward from the base frame within a span, so just must make corrections on the first frame on which they're necessary. Making a change a few frames later will not help on the previous frames.

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Todd Kopriva, Adobe Systems Incorporated
After Effects quality engineering
After Effects team blog
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Victor Camacho GuerreroRe: rotobrush workflow
by on Mar 20, 2014 at 4:32:48 pm

Thanks a lot for your answer Todd.

that is what I thought too but seeing on the help documentation of After Effects I found this.

"The influence of each corrective stroke propagates forward or backward to affect all frames in that direction within the span, regardless of when the stroke is made. For example, if the base frame is at frame 10, you make a corrective stroke at frame 20, and then you make a corrective stroke at frame 15, then frame 20 will be affected by both of these corrective strokes—just as if you had made the corrective strokes in the other order."

http://helpx.adobe.com/after-effects/using/roto-brush-refine-matte.html#WS3...

When do you usually create new spans? When the objects have a new pose?

Many thanks


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Todd KoprivaRe: rotobrush workflow
by on Mar 20, 2014 at 5:49:35 pm

What that section of the Help is trying to tell you is that corrective strokes only propagate in one direction: away from the base frame. If you're working forward in time, corrective strokes propagate forward; if you're working backward from the base frame, corrective strokes propagate backward.

I tend to create new base frames (and therefore new spans) any time there is a significant change in the scene. I use lots of little spans. It also helps with performance.

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Todd Kopriva, Adobe Systems Incorporated
After Effects quality engineering
After Effects team blog
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Victor Camacho GuerreroRe: rotobrush workflow
by on Mar 20, 2014 at 6:06:27 pm

I see, thanks for that.

a couple of more things. After adding some corrective strokes , the edges start flickering, so I was wondering how do you exactly add corrective strokes that dont flick. Using small brushes ? big ones?

When you are creating new spans, that doesnt give you jumps in the mask and as well flickering issues?

usually when I roto, I always keep the shape as much as i can, without moving points. I try to skew, rotate, scale and so on. Keeping the whole mask structure to avoid boiling the edges. Is there any trick like that in rotobrush?

Many thanks!


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Roland R. KahlenbergRe: rotobrush workflow
by on Mar 20, 2014 at 10:11:59 pm
Last Edited By Roland R. Kahlenberg on Mar 20, 2014 at 10:13:13 pm

Boiling edges is a good indicator that RotoBrush may not be the tool for the job. In effect, there is insufficient contrast between your roto object and its background.

Having said that, the Refine Hard Matte effect has a Reduce Chatter prop which helps reduce boiling artefacts.

You can combine traditional roto with Rotobrush. The workflow is to RotoBrush, followed by subtracting the boiling areas and then using traditional roto techniques for this area.

HTH
RoRK
Latest AE Workshop - MoGraph Intensity - Shapes & Text

Intensive mocha & AE Training in Singapore and Other Dangerous Locations

Imagineer Systems (mocha) Certified Instructor
& Adobe After Effects CS6 ACE/ACI


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Todd KoprivaRe: rotobrush workflow
by on Mar 20, 2014 at 10:15:42 pm

Roland's answer was essentially the one that I was about to give.

You can also use the Refine Edge tool (and its cousin, the Refine Soft Matte effect) to help clean up the edges in areas where there is semitransparency and fine detail.

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Todd Kopriva, Adobe Systems Incorporated
After Effects quality engineering
After Effects team blog
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Victor Camacho GuerreroRe: rotobrush workflow
by on Mar 21, 2014 at 9:23:11 am

I see, that is what I was actually thinking. Using mocha to clean all these details.

Many thanks guys!


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Mark DizzRe: rotobrush workflow
by on Mar 21, 2014 at 5:09:47 pm

I use my rotobrushed layer as an alpha matte over itself. Then I blur the matte as needed throughout the shot if necessary, I find that easier for me to control and keyframe on and off.


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Victor Camacho GuerreroRe: rotobrush workflow
by on Mar 22, 2014 at 5:06:13 pm

thanks mark, really interesting trick!


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