Adobe After Effects Forum
Rotoscoping tricky shot
Rotoscoping tricky shot
by Mike Poliskey on Feb 6, 2019 at 8:05:06 pm


I need to rotoscope a girl walking across frame, but the shot is a bit tricky, colourful background with yellows and reds plus some motion blur etc. I've tried to use AE rotobrush but with poor results, it can't recognize edges and generally takes much time with each single frame. I know it's not such an easy subject to track but I'm looking to your advice what would be the most efficient way to do it.
I was thinking about Photoshop sequence as it's selection tool was doing far better.
Any better ideas?

Re: Rotoscoping tricky shot
by Stephen Smith on Feb 6, 2019 at 8:19:35 pm

Rotoscoping is the worst. I would take a look at this tutorial and see if it can give you some tips with the brush that so far isn't working. Keep in mind any rotoscoping will take a long time:

Stephen Smith

Utah Video Productions

Check out my Vimeo page

Re: Rotoscoping tricky shot
by Richard Garabedain on Feb 6, 2019 at 10:36:52 pm

use mocha.. trace each segment of the human body on a different layer...its actually easier than it sounds..I just got into mocha myself

Re: Rotoscoping tricky shot
by Robert Olding on Feb 7, 2019 at 4:07:38 pm

Just as Richard says ... rotoscope different segments of the body separately. It will still take time but you'll get a much better result.

Robert Olding

Studio Eight | Director of Photography
Minneapolis, MN

Re: Rotoscoping tricky shot
by Michael Szalapski on Feb 7, 2019 at 9:44:47 pm

You could even use motion tracking to aid you in your masking. It all depends on how the shot looks. The pro tip about making a different mask for each body part is essential. Also, don't rotoscope everything. Just roto the parts that need it! (Unless you're completely replacing the background, you'll likely not need to do her whole body.)

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.

Re: Rotoscoping tricky shot
by Mike Poliskey on Feb 8, 2019 at 11:42:41 am

Alright, so I made few tests and it looks like mocha gives the best results. I will need to make some retouch anyway so here is another question. There is a paint tool which I never used before, but now I'm thinking to paint on matte previously created with that mocha tracking. This way I could correct imperfected edges. I'm looking into settings and can paint on a single frame, however am wondering if there's an option to jump ahead few frames, make another painting, so the frames in between will adjust to outsides? If you know what I mean๐Ÿ˜‰

Re: Rotoscoping tricky shot
by Kevin Camin on Feb 19, 2019 at 6:12:46 am

I know this isn't helpful at this point, but with keying or roto-scoping the ideal condition is a really sharp image, meaning, shooting with a fast shutter speed for moving objects. At the studio I work we aim for a 22.5 degree shutter. It takes a lot of light but gives good edges. You can always add motion blur back in later.

Sort of like the Mocha solve, you might want to apply different strategies for different parts of the image. Maybe roto for parts, but then you might have to animate a mask for other areas.

Best regards,

Kevin Camin

Re: Rotoscoping tricky shot
by Mike Poliskey on Feb 19, 2019 at 4:27:25 pm

Good advice is always valuable ๐Ÿ‘ Thx!

Re: Rotoscoping tricky shot
by Ross Shain on Feb 19, 2019 at 5:58:45 pm

Depending on how much roto work you have, you might want to look at Mocha Pro. The free Mocha AE has the ability to use planar tracking to drive roto shapes. Definitely break each limb and large area (head, torso, etc) into its own shape.

Mocha Pro plug-in has some more advanced tools for roto including new magnetic spline and freehand tools. This video might help:

Ross Shain
Boris FX / Imagineer Systems