Rotoscoping and Mask Tracking Techniques

In this chapter, we will look into rotoscoping using the Roto Brush tool and mask tracking. These are two essential techniques used in video editing and compositing. These techniques are utilized to isolate and manipulate specific sections of a video or add visual effects to targeted areas, unlocking new creative possibilities. They enable object isolation, intricate animation creation, precise color correction, and the integration of compelling VFX. We will also learn how to use the Content-Aware feature in After Effects, which lets you remove unwanted objects or areas from video footage.

The main topics we will cover in the chapter are as follows:

• Using the Roto Brush tool for quick and precise rotoscoping
• Using the Pen tool to create roto masks
• Tracking masks on moving objects using built-in tracking
• Removing unwanted objects from video clips using Content-Aware Fill

Technical requirements

The files for this chapter can be found in the Chapter 8 folder at https://packt.link/gbz/9781804617281.

Before starting this chapter, it is beneficial to preview the final output and end project file provided in the Chapter 8 | lesson 8 exercise files. By doing so, you will gain a clear understanding of the desired outcome and have a visual representation of what you will be working toward throughout the chapter.

Previewing the final output allows you to see the completed project, demonstrating how the various elements, effects, and animations come together. You can observe the overall look and feel, the arrangement of different components, and how they interact with each other. This preview serves as a reference point, giving you a target to aim for as you progress through the chapter.

What is rotoscoping?

Rotoscoping is the process of manually tracing over a subject in a video, frame by frame, to create a matte or mask. This technique is often used to isolate an object, character, or any specific element in a video clip, allowing you to apply effects or change the background while keeping the subject separate from the rest of the scene.

In After Effects, you can perform rotoscoping in two ways:

• One way is by using the Pen tool to draw around the subject in each frame, creating a mask path for each frame. This can be a time-consuming process, especially for complex scenes, but it offers a high level of control and precision.
• Another way to do rotoscoping is to use the Roto Brush tool, which is a powerful tool that can be used to quickly and easily isolate objects from their background. By using artificial intelligence, it monitors the object’s motion, reducing the need for careful frame-by-frame adjustments.

Now that we have understood...

Opening up the project

For this lesson, open the project in the exercise files of this chapter as follows:

1. Open After Effects.
2. To open the project, click on Open Project in the After Effects startup window. Alternatively, you can go to File | Open Project... in the menu bar.
3. In the file browser, locate the Lesson8_start.aep project file in the Chapter 8 folder of the exercise files and open it:

Figure 8.1: The Lesson8_start project with the default workspace

The project has two compositions, which we will be using to learn about rotoscoping and masking. Keep the project open for the rest of the chapter.

Next, we will be using the Roto Brush tool in After Effects to rotoscope and mask the walk-in forest layer in the rotoscoping composition.

Using Roto Brush for rotoscoping

The Roto Brush tool is a powerful feature in Adobe After Effects designed to streamline the rotoscoping process, making it faster and more efficient. Traditionally, the rotoscoping process could be time-consuming, especially for complex scenes, but the Roto Brush tool changes the game by utilizing artificial intelligence for automated object isolation and motion tracking.

Note

The Roto Brush tool also has the Refine Edge tool, which can precisely incorporate delicate elements, such as wisps of hair, within specified regions of the segmentation boundary. We won’t be using this tool because we don’t have the feathered regions or hairs.

We will be using the Roto Brush tool to extract the man in the Walk in Forest.mp4 video, which is in the Chapter 8 folder. This will allow us to change the background appearance and add text between the men and the background.

Follow these steps to use the Roto Brush tool:

1. Locate the Rotoscoping...

Working with mask tracking and Content-Aware

We will now use the Pen tool and the Content-Aware feature in After Effects. The Pen tool in After Effects is a versatile instrument for creating precise shapes, masks, and paths with intricate control. Its flexibility makes it essential for tasks such as rotoscoping, precise object isolation, and detailed motion graphics creation. Content-Aware Fill in After Effects is an advanced feature that intelligently analyzes and removes unwanted objects or elements from a video, seamlessly filling the gaps with surrounding content. It streamlines the editing process, allowing effortless object removal and clean visual compositions in video projects.

Let’s explore the process of creating a mask using the Pen tool, utilizing the mask tracking feature, and finally, employing After Effects’ Content-Aware panel to remove an unwanted object.

We’ll be working with a composition named Working on Laptop, which is included in the...

Summary

In this chapter, we have learned the fundamental techniques of rotoscoping using the Roto Brush tool and mask tracking, which are crucial in the realms of video editing and compositing. These techniques enable the isolation and manipulation of specific elements within a video, allowing for the addition of targeted visual effects.

Additionally, this chapter covered the utilization of the Content-Aware feature in After Effects, a powerful tool that facilitates the removal of unwanted objects or areas from video footage. By mastering these methods, you can achieve impressive and seamless results in your projects.

In the next chapter, we will learn about how to do chroma keying in After Effects using the key light effect. In short, chroma keying is a technique that’s used in video effects to replace a specific color (usually green or blue) in the footage some other media as the background, allowing the merging of two separate images or video clips.