3D Tracking Overview

[00:00:00] Let's 3D track the shot. For the sake of

[00:00:00] time, we're going to speed through this

[00:00:00] process. Our shot has a nice steady

[00:00:00] camera move and a lot of detail in the

[00:00:00] scene. It should work pretty well using

[00:00:00] After Effects's built-in camera tracker.

[00:00:00] Starting with the D noiseis plate. Let's

[00:00:00] make a fresh pre-MP and name it

[00:00:00] pre-track. I found that the camera

[00:00:00] tracker plugin works best if you convert

[00:00:00] the footage from linear ASUS CG to sRGB

[00:00:00] first. This will only apply if you're

[00:00:00] working in linear ASUS CG like we are.

[00:00:00] Once we've done that color adjustment,

[00:00:00] we'll pre-mp it again to make sure that

[00:00:00] the camera tracker effect will

[00:00:00] acknowledge it. We'll plop the camera

[00:00:00] tracker effect on there and let it

[00:00:00] simmer.

[00:00:00] We can increase the size of the markers

[00:00:00] if they're too small to see.

[00:00:00] Now, we can go through and hunt down

[00:00:00] erroneous trackers. You can click and

[00:00:00] drag around multiple markers at once and

[00:00:00] hit delete on the keyboard to get rid of

[00:00:00] them. It's a red flag if you see some

[00:00:00] markers that are uncharacteristically

[00:00:00] giant. Especially watch out for markers

[00:00:00] that are on moving objects. It doesn't

[00:00:00] take very many wacky markers to really

[00:00:00] mess up your track.

[00:00:00] Under the advanced tab, we can see the

[00:00:00] average error as a rough gauge on how

[00:00:00] good our track is. The lower the better.

[00:00:00] And it looks like we're actually at a

[00:00:00] good spot already. As we clean up the

[00:00:00] markers, you'll see the number update.

[00:00:00] Once we're happy, let's set the origin

[00:00:00] to a nice spot in the center of the

[00:00:00] scene, close to all the areas we'll be

[00:00:00] working with. Note that I'm selecting as

[00:00:00] many markers as I can that are on a flat

[00:00:00] surface in the scene. This will help

[00:00:00] give us a good ground plane and origin.

[00:00:00] Once the ground plane is set, we'll

[00:00:00] create some nles and the camera.

[00:00:00] Let's place a solid where the ground

[00:00:00] plane is.

[00:00:00] Now I'll create a couple more solids to

[00:00:00] help with the placement of the monitors.

[00:00:00] Again, just using the markers that we

[00:00:00] want that are on the correct plane.

[00:00:00] I'm going to throw a checkerboard on

[00:00:00] each of these solids. They're super

[00:00:00] handy for reviewing the track.

[00:00:00] At some point during this, I like to

[00:00:00] jump into the top view and just double

[00:00:00] check that the solids that we're placing

[00:00:00] are lining up nicely with all those nles

[00:00:00] in 3D space.

[00:00:00] When we play back our track, we want to

[00:00:00] make sure there's no jittery motion or

[00:00:00] small bumps.

[00:00:00] Now, I'm going through one last time to

[00:00:00] grab any markers that I think might have

[00:00:00] a position in 3D space that'll be useful

[00:00:00] when we're compositing other elements.

[00:00:00] Be cautious with generating too many

[00:00:00] NLES in your scene. It can quickly bog

[00:00:00] down the user interface. You might only

[00:00:00] need NLES in a few key locations.

[00:00:00] If you find yourself in a scenario where

[00:00:00] you're having to scale the NLES by

[00:00:00] 10,000% to see them, then you might need

[00:00:00] to scale the entire scene to be more

[00:00:00] workable, you can do this by creating a

[00:00:00] 3D null, parenting all of the 3D objects

[00:00:00] in the scene, including your camera, to

[00:00:00] the null, and then scaling that null. If

[00:00:00] you delete that null, you will then see

[00:00:00] the new scale values on all the objects.

[00:00:00] It may take some playing around to find

[00:00:00] the best scene scale. Note that once

[00:00:00] you've altered the overall scene scale,

[00:00:00] it will make it difficult to generate

[00:00:00] new NLES again from your original camera

[00:00:00] tracker. I like to use CC Power Pin to

[00:00:00] corner pin the checkerboard onto the

[00:00:00] monitors. It's handy to have its

[00:00:00] viewport guides and also its expansion

[00:00:00] controls.

[00:00:00] Once that's done, we'll make sure that

[00:00:00] the corners stay put throughout the

[00:00:00] entire shot. I like to put a key frame

[00:00:00] at the start and one at the end just to

[00:00:00] be safe and make any small tweaks if

[00:00:00] needed.

[00:00:00] We'll do the same for the right monitor

[00:00:00] and then view our handywork carefully

[00:00:00] checking that the track is locked on

[00:00:00] throughout the entire frame range.