Clone people (to become en army) in After Effects 7

[Mark Suszko]

A *very simple but limited* method:
Lock the camera shot down and don’t touch it. Shoot a “plate” of just that backdrop.
Next: Put your army men or warriors or whatever in the shot in one spot within camera view, act out the scene, move them to another area of the shot, repeat with variations, etc. as many times as you need to. Never move the camera.

Now you can composite these without necessarily needing precise rotoscoping. You might get awy with just a diffreence key or loose vector mask. Google up a BBC documentary some British guys did; thye re-created the entire Normandy landing with just five guys, and one of those was the cameraman. They used the technique outlined above.

If you want to add camera moves, you will need an expensive motion-controlled camera rig, or to shoot in very high def and move the frame in post.

The fancy way to do this is with CGI, google “massive” and “WETA digital/LOTR”.

[Liv Fredriksson]

Aaaah! That is exactly what I´m looking for!

I was just wondering… how do I use the difference key to mask out only the persons moving in my shootings? I suppose they filmed them running and climbing several of times and then masked out the persons and put the onto the backdrop.

Is there any effect that mask out the moving parts in an movie?

The camera do not have to move…

[Mark Suszko]

Difference key looks at the pixels of the image and recognizes the ones that are different from the original bare “plate” shot. My wife’s iMac iSight webcam has this built in: you step out of the camera view for five seconds so ti can “grab” the background, then it can key in any motion or still file you choose. So you can look like you’re talking online from the front seat of a moving roller coaster or the beach at Waikiki. Its a little cheasy but it is realtime.

For your battle scene, you might also want to combine the layers using different composite modes like “multiply”. Play with the settings and see what works. In FCP, it’s in the drop-down menu at the top called “Modify”.

[Stuart Elith]

Be warned that difference Key almost never works acceptably in my experience (and many others’). Even with locked off footage I have usually found it creates poor results with crunchy edges… partially due to compression and noise, which you can’t really avoid.

But as mentioned, if you have locked off your shot you can draw rough masks around the people and they will sit into the scene pretty well as the backgrounds will line up. When people overlap each other you will probably have to rotoscope them unless you manage to get the difference matte working.

[Liv Fredriksson]

Thanx for all your help everybody!

I think I´ll shoot it so they never cross eath other path and then draw a rough mask around them as you said 🙂

Thank you a lot!

[Christopher Pitts]

Can this be done so foreground people can overlap background people some? I need to shoot a music video where one individual is playing all the instruments. I get locking the cameras down but what editing set up is best for compositing? AE? Mocca? Premiere? Using which effects?

[Mark Suszko]

Yes, if you put each actor with alpha channel on his or her own layer, you’ll have to do some planning as to which actor needs to go on which track layer in order to get the overlaps correct. Should work fine in any NLE or compositor. Depending on the quality of the keyer and the footage.

[Christopher Pitts]

I have Premiere and AE, can you elaborate on the steps I should follow to get down the road with this? I ask because there are a lot of different options with keys in both programs. I can cut live action and fix stuff till the cows come home but this project puts me in some new realms.