Network rendering with watch folders and render engines

You can render one or more compositions from a project using multiple computers over a network in a fraction of the time that a single computer would require. Network rendering involves copying the project and source files to a networked folder, and then rendering the project. (A network of computers used together to render a single composition is sometimes called a render farm.)

If you have a full licensed copy of After Effects, you can set it up to work with render-only versions of After Effects called render engines. Your license entitles you to install as many copies of the render engine as you want on your network, as long as one activated copy of After Effects is installed on that network.

You install render engines in the same manner as the full version of the application, but you do not activate them. You run the render engine using the Adobe After Effects Render Engine shortcut in the Adobe After Effects CS4 folder. (See Install the software.)

You cannot use a watch folder and multiple render engines to simultaneously render a single movie file. However, you can use multiple render engines to render a movie as a sequence of still-image files. You can then use a post-render action to create a single movie file from that still-image sequence. (See Post-render actions.)

When you have multiple render engines on multiple computers monitoring a watch folder, they cooperate to achieve optimal efficiency. If your queued render items are set to Skip Existing Files (a Render Settings option), the render engines all work on a single render item at once—no render engine renders any frame another render engine has already worked on. If this option is not selected, each render engine handles a render item itself.

Rhys Enniks provides a video tutorial on his website that demonstrates the use of multiple computers on a network to render a composition with a watch folder.

Computer with full version of After Effects (A) saves a project and all source files to a folder (B) on a server. Computers with the render engine installed (C) open the project and render a still-frame sequence to a designated output folder (D) on the server.

Network considerations

When working with multiple render engines on multiple computers, keep in mind the following guidelines:

  • When possible, identify folders using absolute file paths so that the paths are correctly identified for all render engines. Identifying folders using absolute file paths may mean mapping network drives to a particular drive letter on all computers (for example, H:\renders\watch\). Avoid using relative paths (for example, \\renders\watch).

  • Each Macintosh computer monitoring the watch folder must have a unique name. Because the default names of computers are often identical, you should rename your computers to not use the default name.

  • Make sure that all servers and clients (computers monitoring the watch folder) have hard drives with unique names.

  • Do not use the same computer to serve a watch folder and to run After Effects in Watch Folder mode. Use a dedicated server that’s accessible to all render engines to serve your watch folder.

  • Do not render to or initiate Watch Folder mode on the root of a volume or a shared folder that appears as the root when viewed from another computer. Specify a subfolder instead. Also, avoid using high-ASCII or other extended characters and slashes in filenames. For multiple-computer rendering, After Effects includes the Multi-Machine sample template that you can use as a starting point.

When rendering across a network that includes volumes using different network or operating systems, such as Windows, Mac OS, Novell, and UNIX, make sure that you specify output files using a file-naming convention that’s compatible with all rendering or destination volumes.

Project considerations

Make sure that you install all fonts, effects, and encoders (compressors) used in the project on all computers monitoring the watch folder. If a computer monitoring the watch folder can’t find fonts, effects, or encoders used in a project, the render fails.

When you install an After Effects render engine on a computer, it contains all the plug-ins included with After Effects. If a composition uses a plug-in from another manufacturer, the plug-in must be present on all computers that will render the composition. However, support for network rendering varies among plug-in manufacturers. Before you set up a network to render effects created by third-party plug-ins, see the documentation for your plug-ins or contact the plug-in manufacturers and get answers to the following questions:

  • Does the license agreement for the plug-in allow installing multiple copies on a network for the purposes of rendering?

  • Are there any other limitations or tips that apply to using the plug-in for network rendering?

Collect Files folder considerations

When you use the File > Collect Files command, files relevant to a project are copied to a single folder. This folder includes a copy of the project file, a render control file (RCF), and other files, depending on the options you choose in the Collect Files dialog box. If you save the Collect Files folder to a networked computer other than a server, don’t run a render engine on that computer. Avoid saving the Collect Files folder to a local disk, the root level of a disk (such as C: in Windows or the Macintosh HD in Mac OS), or a shared folder, all of which can signify different locations to each render engine. All render engines must interpret the path in the same way.

Once the collected files appear in the watch folder, all monitoring render engines start rendering automatically. If you prefer, you can use the Collect Files command to store compositions and their source footage to a specified location and then initiate the watch-folder rendering process later. Doing so renders the projects in alphabetical order, rather than the order in which they were saved to the location.

Set up watch-folder rendering

  1. Install the After Effects render engine on as many computers as you want to involve in network rendering. (For information on installing After Effects as a render engine, see Install the software.)
    Note: If rendering time is unusually slow, you may be rendering to too many computers, and the network overhead required to track rendering progress among all computers is out of proportion to the time spent actually rendering frames. The optimal number depends on many variables related to the network configuration and the computers on it; experiment to determine the optimal number for your network.
  2. Create a watch folder called AE Watch Folder on a computer that’s accessible to all of the After Effects render engines on your network.
  3. In each render engine, choose File > Watch Folder, and select the watch folder that you’ve created.
  4. Create your projects and compositions, and set them up in the render queue with the render settings and output modules you want to use. (All render items in the project must have output names; otherwise the Enable Watch Folder Render option in the Collect Files dialog box isn’t available.)
  5. Choose File > Collect Files to copy completed projects to your specified watch folder. Once you choose Collect Files, After Effects copies the project or composition and all source files to the watch folder.
    Note: After Effects can’t copy source files that are larger than 2 GB using the Collect Files command: you must copy them manually to the (Footage) folder in the Collect Files folder.
  6. Choose For Queued Comps from the Collect Source Files menu (unless you’re manually moving source files), and then select Change Render Output To. This option creates a folder on the networked server for rendered files—all of the render engines need access to this folder to complete their rendering tasks.
  7. Select Enable Watch Folder Render, click Collect, and name the Collect Files folder.
  8. Save the Collect Files folder to a networked computer, preferably to a networked server.
  9. Monitor the progress of the render engines by using a web browser to view HTML pages saved in the watch folder. After Effects generates these pages automatically when the rendering begins. Click the Reload button in your browser to see the updated status. These HTML pages describe any errors that occur.

    After Effects renders the item to the specified destination folder and, if necessary, to the overflow volumes you have specified in the Output preferences (see Overflow volumes and segment settings). When After Effects finishes rendering all of the queued items in a given project, it closes that project without saving it and then scans the watch folder for new projects to render. Because it doesn’t save the project, After Effects ignores any Post-Render Actions in the Output Module settings dialog box that specify to import the item when it is rendered.

Track dependencies of a watch-folder render

You can track render dependencies when you render over a network by setting Post-Render Action options. When you set these options, After Effects confirms that all of the items that it needs to render are ready and available. For example, if one item depends on another to render, and the first has not finished rendering or has received an error, the second does not render.

You can use this process to render a single QuickTime or AVI movie from a watch-folder render. The movie is actually created on only one computer.

Note: This procedure assumes that you have already created a multiple-computer watch-folder.
  1. In the Render Queue panel, drag the output module to the Project panel. After Effects creates a placeholder for that item’s output.
  2. Drag the placeholder back to the Render Queue panel.
  3. Set the render settings and output module settings for the placeholder, and click Render.

Start in watch-folder mode

Watch-folder mode applies only to rendering from a folder on your local computer.

  • To start After Effects in watch-folder mode automatically, save a project with the filename Watch This Folder.aep. After Effects watches the folder containing the project if you open that project.
  • To start After Effects in watch-folder mode when you start your computer, create a shortcut (Windows) or alias (Mac OS) to the Watch This Folder.aep project and move it to your Startup folder (Windows) or your Startup Items folder (Mac OS). After Effects watches the folder containing the project if you open that project.
  • (Windows only) To start After Effects in watch-folder mode from the command line, choose Start > Run, and then enter the following, modifying the application path to the exact name of the folder in which you installed After Effects, and replacing C:\[temp] with the path to your watch folder: "C:\Program Files\Adobe\Adobe After Effects CS4\Support Files\afterfx.exe" -wf C:\[temp]
    To start the After Effects render engine rather than the full version of After Effects, use the -re option with the command.
    Note: You can also use this command line in batch files.