(3.11.15) Yesterday was another great session, we started off looking at different camera settings to achieve the best recording to work with, and what composition settings to use in after effects to minimise compression and loss of pixels. Our first task was to set after effects to the motion tracking workspace layout, then track a dot on a box, from footage Jon recorded in his office. With after effects being on the less advanced/powerful side of motion tracking, Jon told us about a few ways that will stop the tracking spot from keeping on top of it’s target, and how you can stop this before you even start recording, never mind getting into post production. The first part was a dot on a box with a fast shutter speed, which ran off screen. Everyone soon realised that as soon as the dot we were trying to track went out of frame, after effects had a panic attack and the tracking dot went all over the place, even when the original point came back into frame. It’s not clever enough to automatically find it again, so don’t let your tracking point go out of shot.
We then had to do the same for a slow shutter speed. It turns out a lower shutter speed works a lot better, as it has a less erratic pattern for the software to follow, and a way to make the tracking point lose it’s target is make it so fast it can’t keep up with the rapid colour change and follow it. The slow shutter speed footage also didn’t leave the frame which is a bonus. After we got a complete track of the selected point, we had to match up a checkered square to move in the same motion with it, however it was a little off centre while moving, so we moved the anchor points, and adjusted the rotation and position so they matched up. However we still had to add depth as the box rotated along a Z axis. We’ll come back to this bit.
Next task: Sky Replacement. (9.11.15)
Apparently the most common thing to do in VFX, we started by importing our footage and tracking it with two points. The sky is supposed to move at a slower speed than everything else, so we drew a null object and attached the motion tracking we had done to it, then parented the sky to the null object. After this we messed about with the blending mode to remove a black strip at the bottom of the image, and adjusted it as needed to blend in with some feathering to look realistic. Finally we messed around with adding a sun, by creating an eclipse and adding a fast blur, changing the colour, opacity, and sharpness.
Sorry about the vagueness of the sky replacement, I forgot to publish this because I was meant to come back to it to add to it, but didn’t remember until updating the blog for this week. My bad.