Using Green Screen: Combining Animation with Live Action
The magic of filmmaking gives filmmakers the opportunity to take their audience into worlds where they have never been, and one of the easiest way to do this is by using a green screen. Sometimes it will be fantastical, like a cartoon, where there’s no pretense of reality, and other times it will be some sort of hybrid that is clearly not ‘the real world.’ Then there are times it’s supposed to look like the world we live in.
Step 1: Choose What Type
- Cartoons: Classic examples of cartoon characters with live-action people are Windsor McKay and Gertie the Dinosaur, Gene Kelly and Jerry the Mouse, and of course “Roger Rabbit.”
- Pseudo-Reality: This is more similar to the work of someone like Ray Harryhausen (“The 7th Voyage of Sinbad”), which combined stop-motion animation with live-action. This type of animation, often used with pre-CGI animated monsters, has a resemblance to the real world, but the audience clearly knows that those moving skeletons are not real.
- Reality: Usually, the reality factor is relegated to high-end CGI systems. However, there are programs like Maya and Softimage that filmmakers can use to create realistic looking animation to go with live-action footage. Perhaps making armies of zombie pirates is more than you’re up for, but what if there’s an animated raven that pursues your protagonist? You can animate that with Maya or Softimage. We’ll use that as our example, but it's the same technique for all three of these combination types.
Step 2: Plan It
In our hypothetical shot, your live-action protagonist is moving down a canyon from the foreground to the background. The raven that will torment the protagonist is going to follow him. First, familiarize yourself with your software (Maya is available and will give you professional results), find your location, and shoot the live-action.
Step 3: Animate It
Take your live-action footage, then animate the raven to match the actions of the live-action, frame-by-frame. This is the best way to match the two. Animate to match according to where the live-action is on the screen. As a tip, keep the interaction broad. If you want the two characters, animated and real, to fight, you will need to animate one against the other with exact precision. (Note: one of the key elements of green screening is lighting. Watch your highlights and backlights. If the live-action lighting comes from the right and shadows fall to the left, keep that consistent with your animation.)
Step 4: Put It Together
After you’re satisfied with your animation, you can composite with a program like Shake or FinalCut. Import both files in, and composite them together. If the timing is off a little, you can still adjust it forward or backward, in either direction. Learn from the professionals; they often have to do multiple takes to make sure it lines up with the results they’re after. (But the audience never sees those takes. The only one that matters is your final take.) It’ll take time, but the end results are worth it.