After Effects is a fantastic tool for VFX work. This is especially true for motion tracking. However, the tracker you use to motion track your footage might not be the best choice depending on your specific clip. Let’s take a look at six different ways to execute motion tracking in After Effects and discuss when certain tracking features should and shouldn’t be used.
When to Use It: Very quick 2D tracking situations centered around a single point with no warping.
使用時機 : 非常快速2D移動情況,中心環繞一個點，並且沒有包覆到。
The single-point tracker built into After Effects has long been a go-to tool for motion artists, but you need to be careful with single-point tracks because footage doesn’t normally shake in 2D space only. After Effects uses contrast to find track points, so you’ll need to make sure you set your tracker on a well-defined point. If you’re in a rush, one-point tracking will work, but for most professional circumstances, you’ll want to at least use two-point tracking.
In this tutorial fromLive Tech Australia, we take a look at how to use the single-point tracker in After Effects.
這個教學來自Live Tech Australia，我們來看如何在AE使用單點Tracker。
2. Two Point Track 2點追蹤
When to Use It: On footage with mild to moderate levels of camera shake.
使用時機 : 當素材有輕度到中度程度的攝影機晃動。
Two-point tracking is fantastic for simple camera movements, as long as there are a few contrasted elements for the tracker to track. Two-point tracking is notably superior to single-point tracking because it can track rotation and scale, not just position.
If you do a lot of commercial or sci-fi work, then you probably do a lot of screen replacements. In order to help make screen replacements easier, After Effects has a built-in corner pin tracker that is designed to work with any four point surface. While it’s designed to work with screens, it can also work with picture frames, signs, and simple surfaces. In this video tutorial from LinkTCOne, we take a look at how to use the corner pin tracker to replace a picture frame inAfter Effects.
When to Use It: Matte painting, set extensions, and compositing.
One of the most powerful features to hit After Effects in recent years is the 3D camera-tracking tool. The tool essentially automatically creates dozens of track points in your footage and allows you to select which ones to use after the computer processes the footage. This is your best tracking option directly in After Effects. However, the 3D camera tracker can take quite a while if you have a long clip.
近幾年來，在AE裡最強大火紅的功能，就是3D camera tracking工具。在電腦計算處理過素材後，這工具基本上，在你的素材中自動製造出數個追蹤點，並允許你選擇其一來利用。這是你在AE中最好的追蹤選項，然而如果你有較長的片段，3D camera tracker 會花你較多時間。
This tutorial from thevfxbro shows us how to use the 3D camera tracker to ‘composite’ a Christmas tree into a shot.
這個來自thefxbro將展示如何使用3D camera tracker 在一顆鏡頭合成一顆聖誕樹。
5. Planar Tracking Using Mocha 使用Mocha平面追蹤
When to Use It: Advanced tracking on flat surfaces.
使用時機 : 在平面上更進階追蹤
If you have a very difficult-to-track flat surface, then the planar tracking feature in mocha Pro is the way to go. Unlike After Effects, mocha Pro will use predictive tracking to track the position of an object even if a portion of the tracked object is off screen. Tracking data can then be exported from mocha into After Effects.
如果你有一個非常難去追蹤的平面，那麼在Mocha Pro的平面追蹤的功能是不錯的選擇。不像AE，mocha Pro 使用預測追蹤一個物體位置，即使追蹤物件的部分是在螢幕外。Tracking data可以從Mocha 匯入AE。
This quick video tutorial from short-form video shows us how to planar track in mocha.
6. Spline Tracking 曲線追蹤
When to Use It: Complex camera tracking jobs.
使用時機 : 複雜的攝影機追蹤工作
If you’ve exhausted all of the other options on this list, or simply want the most accurate track possible, then spline tracking in mocha Pro is the way to go. Spline tracking can track any type of shape because you custom create the tracking plane. Essentially, you trace around the object you want to track and mocha will try its best to keep track of the object. Data can then be exported to After Effects.