November 26, 2013

Tutorial: Make an Explosion Look More Realistic Using Keying and Masking in After Effects

After Effects Color Key maskingIf you're interested in incorporating special effects in your films, chances are you're going to work with green screen, stock video, and After Effects to create your composites. In a recent tutorial, Andrew Trice shows us how to use all three in order to composite using keying, as well as utilizing techniques, like motion tracking, linear color keying, and tritone color correction in After Effects. Continue on to find out how Trice got away with setting off an explosion a block away from the Adobe offices in San Francisco.

The first demonstration Trice gives in the video is how to overlay footage shot in front of a green screen onto background video -- pretty straightforward. The second demo, however, shows us how to take a piece of stock video -- in the case, an explosion -- and overlay, track, blend, and mask it over a moving scene.

If you're just getting started with visual effects, learning how to key is probably high on your to-do list -- but the work doesn't end there. Pulling off a good effect means hiding the seams made when combining what is originally in your shot and what you put into it. Trice addresses this issue by showing you how to use several techniques.

First, he demonstrates how to use the motion tracking tool in After Effects in order to match the movement of the effect with the original shot. Next, he uses the linear color keying tool to get rid of the white background of the explosion, then adjusts the colors and softness of the edges to hide the seam. He finishes by applying a tritone color correction, as well as a mask to give the illusion that the explosion only follows the path the buildings provide.

https://www.youtube.com/watch?v=Chbo4KUupyI

What do you think about Andrew Trice's tutorial? Do you have any tips on keying, blending, masking in After Effects? Let us know in the comments.

[via Andrew Trice]

Your Comment

7 Comments

An additional technique is to track to a null rather than the explosion itself. Then parent the explosion to the null which now has the tracking data attached to it. This gives you a little extra flexibility to move around the explosion without having to worry about messing up the keyframes from the track.

November 26, 2013 at 10:31PM, Edited September 4, 11:21AM

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Sean

It's just generally good to track a null and parent assets to it because then you can parent any assets youadd to the null and move them around and only have to get a good track once.

November 26, 2013 at 10:42PM, Edited September 4, 11:21AM

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Tyler

This technique also helps a tonne: http://www.digitaljuice.com/djtv/detail.aspx?sid=372

November 27, 2013 at 12:55PM, Edited September 4, 11:21AM

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Very cool thx for sharing!

November 27, 2013 at 5:47PM, Edited September 4, 11:21AM

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No problem! Also check out http://www.videocopilot.net – Andrew Kramer's tutorials are a quick and painless way to get your compositing skills up to a decent level.

November 28, 2013 at 11:32AM, Edited September 4, 11:21AM

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That is a very useful technique! Thanks. This is really going to help save me some headaches on my current project!

June 23, 2015 at 11:07AM

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Sean M Pennington
Indie Filmmaker
74

Hi there mates, good post and fastidious arguments commented here, I am
genuinely enjoying by these.

June 1, 2014 at 3:58PM, Edited September 4, 11:56AM

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