If You ve Used Other Compositing Programs


If You've Used Other Compositing Programs

After Effects 6.5 Studio Techniques partly grew from my being "The After Effects Guy" on various projects. On The Day After Tomorrow, for example, I joined a team of veteran freelance compositors at The Orphanage, few of whom had ever used After Effects. They were far more experienced with Apple's Shake, Digital Domain's Nuke, and Discreet's Flame. My role was not only to complete my own shots but also to help debug their problems using After Effects, freeing the compositing supervisor's time.

This double duty helped me gain a perspective on what is confusing about After Effects to people who otherwise understand compositing well. Believe it or not, compositing programs do not vary as much in their fundamental workflow as, say, 3D animation programs do. Although After Effects appears to operate completely differently than Shake, Nuke, Flame, and other node-based applications, the fundamental differences are relatively few. To summarize, they are

  • Render order in After Effects is established on the timeline and via pre-composing. The clearest distinction between After Effects and its node-based brethren is its lack of a tree/node interface. Open Project Flowchart view and you see that, under the hood, After Effects tracks rendering order works the same way as these other applications (Figure I.4). After Effects, however, doesn't let you interact this way. (See Chapter 2, "The Timeline," and Chapter 4, "Optimizing the Pipeline.")

    Figure I.4. Project Flowchart view is perhaps the most unrecognizable After Effects view.


  • Transforms, effects, and masks become part of a layer and render in a set order. In After Effects, layers have properties that belong only to them. To an After Effects user, the Shake method of applying a transform to a clip, rather than simply animating a layer's Position property, is a little hard to get used to (Figure I.5). On the other hand, as is explained in Chapter 4, After Effects sometimes enforces a specific order in which certain properties render, and you need to know what that is.

    Figure I.5. A Shake node flow re-creates the set order (masks, effects, transforms, and finally blending modes) in After Effects for a three-layer composite. (Image courtesy of Stu Maschwitz.)


  • After Effects, like other Adobe applications, tends to think in terms of four channels: red, green, blue, and alpha (or transparency). This is a subtle one, but the distinction plays out as soon as you start creating selections for layers (see Chapter 3, "Selections: The Key to Compositing"). Node-based applications tend to encourage you to think of mattes as luminance data, which they are. Like Photoshop, however, After Effects retains through its pipeline the persistent idea of a fourth color channel, the alpha channel, which controls transparency. You will have more success working with After Effects if you are willing to work on building alpha channels rather than combinations of luminance data for transparency.

  • After Effects works always in straight alpha mode, and it handles the conversion from straight to pre-multiplied alpha internally. Not only does After Effects have a persistent idea of an alpha channel, but internally, it is always working with that alpha in straight mode. Chapter 3 covers the few provisions that are given to deal explicitly with pre-multiplication inside of After Effects.

  • There is, alas, no direct equivalent in After Effects to macros. If you've never used an application like Shake, you don't know what you're missing. If you've gone far enough with the node-based application to write your own macros, however, After Effects may leave you scratching your head. It offers little in the way of direct pixel calculation and no way to batch process images via a script. The workarounds typically involve effect plug-ins and pre-composing.

  • Temporal and spatial settings tend to be more absolute in After Effects. Many differences between After Effects and the node-based applications contain both benefits and pitfalls. If you need to carefully manage timing and spatial data (animation), the After Effects timeline offers huge advantages. On the other hand, all layers contain spatial and timing information relative to their composition. In other words, if you create a cool effect on the adjustment layer of a video resolution comp, and then copy the adjustment layer to a longer film-resolution comp, the layer won't cover the whole frame, nor will it last the duration of the new comp. This is something you don't typically have to think about in a node-based application.

  • After Effects lacks support for floating-point linear calculations and high dynamic range images. It's pretty difficult to get used to, but the fact is, the world of high-end compositing has changed dramatically in the last few years around a new model. If you've never worked in a linearized floating-point pipeline with the capability of handling overbright pixels, you may not even be aware of all the compromises you end up having to make to get the light in your scenes to behave naturally. High dynamic range images and a floating-point, linearized pipeline are the waves of the future, but the future is here today for After Effects users in the form of a plug-in set known as eLin. (See Chapter 11, "Issues Specific to Film and HDR Images.")

Of these differences, some are arbitrary, most are a mixed bag of advantages and drawbacks, and a couple of them are constantly used by the competition as a metaphorical stick with which to beat After Effects. The two that come up the most are the handling of pre-composing and the lack of macros.

This book attempts to shed light on these and other areas of After Effects that are not explicitly dealt with in its user interface or documentation. The truth is that Shake, Nuke, and others require that you understand their own issues, such as managing pre-multiplication in your pipeline, to master them. After Effects spares you details that as a casual user, you might never need to know about, but that as a professional user you should understand thoroughly. This book is here to help.



Adobe After Effects 6. 5 Studio Techniques
Adobe After Effects 6.5 Studio Techniques
ISBN: 0321316207
EAN: 2147483647
Year: 2006
Pages: 156

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