COMP ON CAPTAIN MARVEL
FOLLOW ALONG AS SYDNEY’S COMPOSITING SUPERVISOR ALEX FRY DISCUSSES THE INS AND OUTS OF THE COMP REQUIREMENTS FOR A PARTICULAR SEQUENCE IN CAPTAIN MARVEL
One of the trickier things to do in visual effects is making scenarios that are fundamentally unrealistic, seem plausible. When you have a shot that’s anchored in reality, like a modern city in daylight, even if there is a giant alien ship hovering above it, there is plenty to ground yourself to; everyone on the team knows what it should look like, and can point at reference. But things are a lot murkier when you’re trying to make a realisticlooking dreamscape that’s happening in some sort of shared virtual hallucination with an alien super intelligence.
The environment we created for the chamber where Captain Marvel meets with the Supreme Intelligence is for the most part defined by these volumetric light beams coming down from above. These very quickly pose a problem: what’s in the air that’s catching the light? How strong are the lights? If the atmosphere is thick, how can we see out to the horizon? If the atmosphere is relatively clear, we need extremely strong lights to create a volumetric light, but then how bright are the points where that light hits the ground?
These are all issues that very quickly get you into a place where setting up a truly realistic scene in a modern unbiased raytracer becomes impossible. So for a scene like this, most of the passes are bolted together in ways that aren’t physically plausible. Riding the edge and finding a look that feels real, but isn’t, can be a long, drawnout process.
As we develop that look we find some effects that make sense to push back into the renderer, like the temporal chroma split on the light beams. This is the sort of effect we might find the look of in comp, but once we’re happy with it, push it back upstream into the texture that’s generating the beams. Or the look of the horizon, where we worked the look of the distant lights as part of a comp, but then baked them out as an animated lat-long image that could be used in lighting, allowing it to reflect off the water. Many parts of this scene follow this pattern, an iterative back and forth with lighting.
We also used the comp process to try and force some happy accidents. The light beams are delivered from lighting in 16 distinct layers, allowing us a lot of flexibility to art direct the timing and intensity of them in different parts of the frame, and over time. Rather than trying to do that just by eye, we would render out versions of out comps where we would randomise the seed feeding a bunch of our control values. This gave us a hundred or so variations for each setup, which we could all review together in a theatre and then use as the starting point for our comp.