CHAPTER 12
Post-Production and Compositing

Featuring

•  Understanding Video Post

•  Using the Video Post Tools

•  Adding Scene and Image Events

•  Applying Effects Filters

•  Editing with Cuts and Cross-Fades

•  Compositing in Video Post

•  Understanding Alpha Channels

In this chapter you’ll learn about the post-production capabilities available within MAX. This includes editing, compositing, and applying image filters such as Lens Effects within the Video Post dialog window. You will explore the various tools available within Video Post. You will learn about alpha channels and how they are used in compositing. Finally, you will apply what you have learned in an advanced compositing exercise, using a Matte material and Raytrace reflections to manipulate an image and its alpha channel for compositing.

Understanding Video Post

As mentioned in the Chapter 11, we can do a great deal of post-production work inside MAX within the Video Post dialog window. Many beginning MAX users are afraid of using Video Post and avoid it. This may even be part of the reason that Lens Effects are now available in the new Render Effects dialog window. To be fair, there are certain mistakes that are easy to make in Video Post that can be frustrating enough to put anyone off. But once you understand how it works—how the VPQueue “thinks”—you will find it a very powerful post-production tool.

Video Post isn’t a full video editing package like Final Cut, Premiere, or an Avid; it’s not a full video compositing package like Commotion, effect*, or After Effects; but for a single dialog within a 3D program, it’s amazing what you can do with it. And after all, it’s built into MAX—you don’t have to go out and buy (and learn) another software package. You can do regular editing, cutting between cameras and pre-rendered images, and you can also cross-fade and composite between different views or pre-rendered images. You can resize images and change their placement in a composite. You can apply any of the various Image filters, including all of the Lens Effects filters available in Render Effects with some options that are available only in Video Post.

Using Video Post Tools

When you choose Video Post from the Rendering menu, you bring up the Video Post dialog window. It consists of two panes: the VPQueue and the timeline. The left pane is the VPQueue, a list of “events” that are read and carried out in order from top to bottom when you “execute” the queue. The events are commands about what to render, what filter or layer effect to apply, and what to do with the information (whether to save it and how). The right pane of the Video Post window is the timeline, which displays the duration of each event in the queue. As you can see, the Video Post window also has its own toolbar, with many of the same tools we’ve seen elsewhere in the program.

Let’s look at an example of a queue with some events in it, shown in Figure 12.1. Notice that the events are arranged in a hierarchy, like a directory structure on a computer, with the events further to the right nested under events that are above and further to the left. It’s vital to understand and pay attention to this hierarchy when using Video Post, so your queue will be executed in the proper order.

FIGURE 12.1  Hierarchy of events in VPQueue

WARNING Misunderstanding the Video Post hierarchy is the Number 1 thing that screws people up when using the window. If your output event is nested under another event, your output file will contain only the frames of the scene or image event under which it is nested. If your output event is not the last thing in your queue, only the events before it will be saved to disk. In both cases, the other events will be rendered in the Virtual Frame Buffer, requiring all that processing time, but they will not be saved to disk.

In the timeline in the right pane of Figure 12.1, you can see a bar showing the duration of each event. Obviously, it’s similar to the Track View timeline; it’s the same as the score or timeline windows of programs like Director, Flash, or Premiere. The Video Post timeline is separate from the scene timeline referenced by individual scene events in the VPQueue; the Video Post timeline is used to create a “post-process” rendering different from what would be rendered by the regular Render tools. In the Edit Range Bar mode (the only one available without multiple events selected), you can slide the range bars horizontally to change their start and end time within the timeline, or move the start and end points to change their duration.

	NOTE Moving the start and end points changes the spot in the Video Post timeline where the frames of that event will start rendering. It doesn’t change which frame of the scene or input image will be the starting point of that event. To change that, you need to double-click the event; then change the Scene Range (for a scene event) or click Options and change Frames (for an image event).

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