Basic uses for VFX
Where does VFX shine, at the most basic level? Let’s look at two examples of very simple motion tracking and an easy effect to augment a scene.
Wire removal
Anytime you see an explosion that knocks a character back or sends them flying through the air, there are other forces at play. Explosive shockwaves even from the largest explosives used on set are not strong enough to throw a person around like that. As a general rule, if the shockwave is strong enough to knock you over, the blast would probably kill you. However, we’ve been trained to see people getting knocked around by shockwaves as normal.
Action film explosions are much more exciting when it knocks the hero off his feet. If the blast itself isn’t moving the character, then what is? The actor is attached to a wire that is attached to a pulley system manned by someone else on set. When the explosion happens, they pull the actor or stunt double through the air. This presents one problem: there’s a wire in the shot. This is why wire removal is an incredibly common need for VFX.
Even if every stunt and action in a scene is done practically, wire removal by a VFX artist may still be needed. It’s simple to do and involves selecting points for the beginning and the end of the wire, tracking those points over time, then applying the “wire removal” effect within your compositor of choice. This is a great example of how special effects and visual effects teams work together to produce a final image on screen that serves the script and feels as real as possible.
Lightsabers
If you’re a fan of Star Wars, you probably love every minute of lightsaber dueling throughout the films. Something about the lightsaber is foreign and futuristic but still feels classic. That combination makes it a joy to watch on screen. It may surprise you to find out that a lightsaber effect is actually very easy to create in a program like Adobe After Effects.
Much like wire removal, you start by tracking points throughout a scene that will make up the beginning and endpoints of the blade. Then between those two points, you create a white beam with a colored glow around it. It’s simple and you can track a lightsaber in a shot in a matter of minutes.
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Advanced uses for VFX
What is VFX ideal for, at a more advanced level? To answer that, we’ll need to discuss the most complicated piece of visual effects, which is CGI, or computer-generated imagery.
CGI uses 3D models created by CG artists of digital objects with hyper-realistic detail. A rigging artist then rigs those models. The rigging stage is essentially giving the model a skeleton that can move around; it creates multiple points in the body that pivots and behave just like the joints in a real body. The rigged model then goes to an animator, who moves the model in realistic ways throughout a scene.
Once the animation itself is rendered, one of two things will happen. If the scene is entirely CGI, the shot is complete. If there is any real footage element, whether that’s a background or a character placed inside a spaceship, that animation goes to a compositor. The compositor’s job is to marry CGI elements with filmed elements to create a seamless image that feels real. Compositors are masters of techniques like masking, motion tracking, and projection mapping. They also boast a host of other skills that marry footage and 3D together for our favorite films.
