How do I cut out a single element of a video?

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How do I cut out a single element of a video?

Postby koggykage on 07/20/2015, 2:50 pm

Hey guys, so I'm new to after effects... started using it because my buddy and I are editing some of my videos for youtube. So for an intro title I think it'd be cool to have the character I play in the game shooting at the title and making it explode or something. So how can I do this? I'll include a link so you can see what game I'm playing and what I mean.

When you watch the video, just pick out any one of the characters and follow everything they do- just that one champion. I want to take everything else around that out.. and use that as a layer in AE. Any feedback helpful!

https://www.youtube.com/watch?v=fjLJDNb0c90
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Re: How do I cut out a single element of a video?

Postby gregalan on 07/20/2015, 5:11 pm

Hi koggykage, welcome. The thing you are looking for is called Rotoscoping, basically drawing masks around your character. A Google search will give you lots of tutorials, but be warned it's a pretty tedious process.
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Re: How do I cut out a single element of a video?

Postby Farmfield on 07/21/2015, 5:38 am

^this!! :)

The trick with rotoscoping is using a lot of different masks, all as simple as possible. As an easy to understand example, think you got footage of someone walking and you want to extract just the person from the background, you'd split the body up by parts you know move separately, so you'd create one mask for the head, one for the upper body, one each for the upper and lower arms and upper and lower legs and/or with separate masks for each hand and foot, if needed. Then you do it mask by mask, and it doesn't matter which you start on, just pick one, when you got that right, you start on the next.

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Another great rotoskoping trick is doing half-way-inbetween keyframing, so start with the first and the last frame, then create a keyframe in the middle. Then create keyframes in the middle of keyframe 1-2 and one between 2-3, then you create new keyframes inbetween those keyframes. Eventually you will come to a point where, when you move your time inbetween two keyframes, the mask is perfect and you can simply create a keyframe without changing it, so it will simplify (and speed up) the work exponentially the longer you split until you finally come to a point where your mask is perfect every frame from start to finish and you continue on to the next mask. :)

Here's some interesting background info...

http://www.fxguide.com/featured/the-art-of-roto-2011/

And before complaining how tedious work this is, imagine they did this stuff manually, painting, back in the day... :D

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Last edited by Farmfield on 07/21/2015, 7:08 am, edited 1 time in total.
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Re: How do I cut out a single element of a video?

Postby plae57 on 07/21/2015, 5:46 am

farmfield is right (he always seems to be right), break the item you are trying to isolate into logical masks. I like to do most of my roto work in Mocha AE. I generally track the part I am going to mask, then on a separate layer draw the mask and link it to the track. You can do this in AE too by using the tracker and a null. Mocha offers you both bezier and splines to create your masks.

If you google "Rotoscoping in After Effects" you will be rewarded with a ton of tutorials
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Re: How do I cut out a single element of a video?

Postby Michael_Szalapski on 07/21/2015, 6:59 am

A wise man once said,
If you start work in the catering industry as a chef, chances are you will spend the first year washing up pots and pans.
If you start work in the effects industry, they give you rotoscoping.


If you want good roto in AE tutorials, I know of an excellent resource.
______________
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Pick two.
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Re: How do I cut out a single element of a video?

Postby Farmfield on 07/21/2015, 7:19 am

Last gig I did, nuclear explosion thingie in my vimeo feed, in the middle of production I just got a mail from the producer asking me if I had time over during Houdini sim's/rendering to do a roto, nothing too complex so of course I told him yes. I've also been in situations where, if I send something off to be rotoed, I'm gonna be locked up until I get it back anyway, so it's just more practical to do it yourself, however boring it is. So roto is just something that is hard to get away from when you're in this field, thus you really benefit from knowing how to make it as easy as possible for yourself. :)

And just generally, if you think being high up in the foodchain makes you immune from doing dirty work, here's the life of a VFX animation supervisor (Hans Brekke @ Tippet Studios, if I remember correctly) - it was up very briefly on Vimeo before he was forced to take it down, but I've managed to get a hold of it and it's just so much fun & so very telling regarding the madness of the industry...



@Plae

I try to keep to what I know is correct, just passing along what I learned from others. :)
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