How to draw a new mask for every frame?

[John Cuevas]

New Mask = Shift + Cntl + N

Johnny Cuevas, Editor
Thinkck.com

“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.

[Angie Taylor]

Rotobrush may be a better option to start off with? Get a rough selection this way.

Then you could also try Layer > Autotrace to create masks from the Alpha created by Rotobrush, make sure it’s set to Trace entire work area.

Finally add Refine Matte effect to add motion Blur, smoothing etc.

Hope this helps.

cheers,

Angie

Angie Taylor animation & illustration for television, film, web and devices

https://www.angietaylor.co.uk
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[Angelo Lorenzo]

Dave and Angie bring up good points. I also strongly suggest using key frames spread out as far as possible and then working inwards if the spaces between keyframes need refinement.

Keyframing a roto every frame is 1) a lot more work than what you need to be doing and 2) always creates edge jitter from poor edge accuracy. Even if keyframe momentum only holds for 3-4 frames, it’s better that way.

[Simon Ruschmeyer]

Dear All,
thank you for your help, it’s so much appreciated.
Imm masking a piece of cloth which a woman folds out and arranges it on the floor, for most of the frames the form of the cloth changes so fast and in so many directios that interpolating the frames seems to be no option.
I tried both working with keyframes from the edge frames inwards and Rotobrush, but did not reach successfull results. It might be because of my low level of knowledge, I think I need to understand the refinement parameters of those methods better, but the masks I got where not excact enough.
In the end I found a workaround: I exported the frames as a image sequence, made a mask for every frame in photoshop and re-imported in After Effects. Maybe not the fastest approach but I am sattisfied with the result.
Thank you so much for your help,
best regards, SImon

[Simon Ruschmeyer]

Dear Dave,
I changed the color of the cloth to a more vibrant red. I first tried to pull a key with primatte bud did not succeed. That’s why I turned to masking it. Which technique would you have suggested?
Best regards, Simon

[Simon Ruschmeyer]

Hey Dave!
Did not know the concept of a garbage mask yet, thanks for the tip, I’ll try it next time!
Take care, Simon