Optimizing Projects


I sometimes surprise directors and effects supervisors with the speed and interactivity I squeeze out of After Effects, even at full 2K film resolution. Here's my secret: As I work, I organize portions of my master comp that I consider finished into their own subcomps, and if they require any render cycles at all, I pre-render them.

You can use your Info window to show you what is rendering as you work. To add descriptive updates to the bottom of your Info palette, go to Display Preferences and check the box next to Show Rendering in Process in Info Palette and Flowchart.


It's astonishing to me how many veteran compositing artists waste redundant rendering time by failing to commit to their own decisions, especially given how easy it is to make changes if you've guessed wrong. For example, on effects shots that begin with a blue-screen key, but develop into very complex shots, artists often fail to pre-render the keying results for fear that they might need to tweak them later. This can add several seconds to an individual frame update and minutes or even hours to a film-resolution render. Every time you want to see the result of a new color correction, you end up waiting for your keyer to redo its work.

The Grid

New with After Effects Professional 6.5 is X-Factor, a plug-in developed by Gridiron Software that distributes the RAM previewing task over any number of peer machines (render nodes) that are available on the network. The results have a nearly linear relationship to the number of render nodes, meaning three computers preview three times as fast as one, assuming they contain similar processors.

Proper use of this feature, however, requires extra open machines and a speedy (preferably switched gigabit) network. Licenses are included for two extra CPUs, and you can purchase additional nodes individually or via a site license.

Remember, however, that X-Factor works on previews only; if you're after network rendering, you must seek a separate solution (see the "Network Renders" section).


After Effects does have a RAM cache (which is further optimized with each major upgrade of the application) to keep track of what has not changed when you make adjustments and avoid unnecessary re-rendering. This is a great feature, but you should not rely on it solely to make your workflow speedier.

Post-Render Options

Happily, the After Effects UI anticipates that you may want to pre-render nested compositions and use the rendered output, without eliminating your ability to go back and change your mind. Tucked away in the Render Queue window, but easily visible if you twirl down the arrow next to Output Module (Figure 4.13), is a menu of three post-render actions. After the render is complete, you can choose

  • Import: Imports the result

  • Import & Replace Usage: Does not eliminate the source comp from the project; only takes its place (or that of any other item you specify) in the project

  • Set Proxy: Makes the rendered output a proxy (temporary substitute) of the source comp (or of any other item you specify)

Figure 4.13. Twirl down the arrow beside the Output Module settings for a Render Queue item and you reveal options to perform actions following the render. The last two options are particularly useful for speeding up future renders, if you apply them to sub-compositions and render those.


If you choose either of the latter two options, a pickwhip icon appears adjacent to the menu. Click and drag from this icon to whatever item in the Project window you wish to replace. By default, the comp that you're rendering is replaced.

What if you choose Import & Replace Usage and need to change your mind later? It's not actually such a big deal, assuming you haven't lost track of the original comp. To change usage back to the comp instead of the rendered footage, hold down the Alt key (Option key) as you drag and drop the comp over the footage in the Project window; this replaces its usage throughout the project. Doing the same type of drag and drop into a Timeline window replaces only the individual instance, which is useful in other cases.

If your intention is only to make your work speed faster, but you anticipate re-rendering everything from scratch when you're ready to create the final render, use proxies.

Proxies

Any visual item in your Project window can be set to include proxy footage. A proxy is an image file or sequence on your drive that stands in for an item in your project. Its pixel dimensions, color space, compression, and even its length can differ from the item it's replacing; for example, you could use a low-resolution, JPEG-compressed still image as a stand-in for a full-resolution, moving image background.

Figure 4.14 shows what an item with a proxy looks like in the Project window. Even though the scale of the proxy is different from that of the source item, transform settings within the comps that use this item remain the same whether the proxy is enabled or not. That's the beauty of it.

Figure 4.14. the left of a footage or comp item in the Project window indicates that a proxy is enabled; a hollow square would indicate a proxy was attached but not currently active. Both items are listed at the top of the Project window, the active one in bold. Rendering with Use Comp Proxies Only would cause the proxy to be used instead of re-rendering the comp in this case.


The "official" use of proxies seems to be as a low-resolution image or clip to stand in for one that is high resolution. However, the feature is also useful for pre-rendering compositions. The Use Comp Proxies Only option (Figure 4.15) is included for just such a case: pre-rendering compositions at full resolution to be used as final elements. The source composition is not blown away by this action; it remains in place but no longer expends rendering resources.

Figure 4.15. Use Comp Proxies Only offers you the best of both worlds with proxies. Source footage can have low-resolution stand-ins that do not appear in the final render, while source compositions have fully rendered stand-ins that save gobs of rendering time thereafter.


Proxies are relatively easy to blow away if no longer wanted. Select the items, and from the item's context menu in the Project window (or the File menu) choose Set Proxy > None (or simply choose to use no proxies at render time).

Network Renders

A single machine can only do so much to render an After Effects project. If your studio is large enough to have a network with more than one or two machines, it would behoove you to look into network rendering, in which all available machines are used to render a shot simultaneously.

There are two basic options for network rendering. The built-in solution is the Watch Folder command. It instructs After Effects to look in a specific place for projects that need to be rendered and to collaborate on rendering them. This works reasonably well on small, intimate networks; the main downside to it is that it has to be set up manually on each machine that will run it. This becomes impractical in a facility with a render farm, a rack of servers dedicated only to rendering, none of which typically has even a dedicated mouse or monitor (and all of which ideally sit in an air-conditioned little room). On a feature film project, the facility might have hundreds of these.

In such a case, consider going to the extra expense and effort to invest in a third-party rendering solution that takes advantage of After Effects' command-line rendering capabilities, such as Rush Render Queue (http://seriss.com/rush/). These programs run scripts that manage the process of rendering an After Effects project on many machines (Figure 4.16). They include a user interface that includes everything you need to intelligently manage a complex set of renders. They can deal with complicated situations, such as machines becoming unavailable or going down during a render.

Figure 4.16. That's not the Render Queue! Rush Render Queue may not be pretty, but it's pretty sophisticated; This Submit panel allows you to specify which CPUs on your render farm will pick up the render, at what priority, how many of them to use to divide the job, and how much time to give each of them to try rendering it before you bail out and go to the next. At big studios, this is indispensable.


However, implementing such a system is not quite as simple as buying a box of software off the shelf and installing it. It requires the skills of a system administrator or equivalent technical expert. Most network facilities have such a person on staff, and many advanced After Effects users are capable of setting this up.

If you want to start with a Watch Folder render, however, and aren't certain how to do it, the online documentation provided by Adobe is complete and helpful. The help topic "Rendering" on the "Network: Using a Watch Folder" page includes everything you need to know, so there's no reason to reiterate it here.



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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