Tracker, Parallel Corner Pin?

[AntDX316]

No one has a good example as to why this matters.

Can someone give a good example?

[David Arbor]

The different tracking types, including Parallel Corner Pin are explained in the After Effects User Guide: https://helpx.adobe.com/after-effects/using/tracking-stabilizing-motion-cs5.html

Scroll down to the Motion Tracking Controls section to read about the different types.

[AntDX316]

The tracking mode to use. The motion tracking itself is the same for each of these modes; they differ in the number of track points and how the tracking data is applied to the target:

• Stabilize tracks position, rotation, and/or scale to compensate for movement in the tracked (source) layer. When tracking position, this mode creates one track point and generates Anchor Point keyframes for the source layer. When tracking rotation, this mode creates two track points and produces Rotation keyframes for the source layer. When tracking scale, this mode creates two track points and produces Scale keyframes for the source layer.

• Transform tracks position, rotation, and/or scale to apply to another layer. When tracking position, this mode creates one track point on the tracked layer and sets Position keyframes for the target. When tracking rotation, this mode creates two track points on the tracked layer and sets Rotation keyframes for the target. When tracking scale, this mode creates two track points and produces Scale keyframes for the target.

• Parallel Corner Pin tracks skew and rotation, but not perspective; parallel lines remain parallel, and relative distances are preserved. This mode uses three track points in the Layer panel—and calculates the position of the fourth—and sets keyframes for four corner points in a Corner Pin effect property group, which is added to the target. The four attach points mark the placement of the four corner points.

• Perspective Corner Pin tracks skew, rotation, and perspective changes in the tracked layer. This mode uses four track points in the Layer panel and sets keyframes for four corner points in a Corner Pin effect property group, which is added to the target. The four attach points mark the placement of the four corner points. This option is useful for attaching an image to an opening door or the side of a bus that’s turning a corner.

• Raw tracks position only. Use Raw to generate tracking data that you won’t apply using the Apply button. For example, you can copy and paste the keyframes for the Attach Point property to the Position property for a paint stroke; or, you can link effect properties for the Stereo Mixer effect to the x coordinate of the Attach Point property using expressions. Tracking data is stored on the tracked layer. The Edit Target button and the Apply button are not available with this tracking option. You can add track points to a tracker by choosing New Track Point from the Tracker panel menu.

[Rick Gerard]

Tracking is a critical component of almost any effects shot requiring you to add something to a moving video. It saves hours when you are rotoscoping, replacing computer screens, or sticking any graphic or effect to any surface. The standard trackers in After Effects track the position of the feature or detail contained in the inside box of the tracker. The movement of that group of pixels is tied to the little crosshairs (+) in the middle of the box by default. It tracks image details in the inner box and looks to the outer bot to try and find the details in the next frame. Motion blur, color changes, shadows, reflections, or anything else that changes the appearance of the pixels in the inner box will throw off the tracker. Many people call the native AE tracker a Point Tracker, which is inaccurate. 

Corner Pin tracking is often used for screen replacement. If you select Corner Pin tracking, you end up with four attach points, and you can distort any comp-sized layer so that the corners will line up with the tracking markers for each point. Corner Pin Tracking is also a convenient way to motion-stabilize an area in the shot. It takes less time and fewer keyframes to paint on the layer or rotoscope or accurately position other effects and make them stay in the right spot if you Motion-stabilize first, add your effect, then put the motion back in the scene.

After Effects also comes with Mocha AE. It is a planer-tracker with a lot more features. It can track shots that are impossible to follow with the standard tracking tools. 

Camera Tracking is another way to attach layers to footage shot with a moving camera. It is a critical part of any visual effects workflow. Not all footage can be successfully tracked. All the trackers require a surface or detail that does not change much over time. You could easily spend a week going over the free Mocha tutorials on the Boris FX website. You could also easily spend a week trying many of the things you can do with the standard trackers. Any time you can track something, you will save time and end up with a better job than you could by setting keyframes by hand. 

Here is an example of how tracking in Mocha AE lets you change the background on the bench at a bus stop. Doing the same thing by hand would be extremely difficult if not impossible.

There are other tutorials in my channel that demonstrate different types of tracking.

My After Effects Quick Tips

[AntDX316]

yeah, definitely it's good

I've made a few before to practice.