TECH TIPS

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VFX Placement Made Easy
XMiL Placer: The Intelligent Visual Effects Spotting Tool
by Dieter Rozek

Digital technology has given filmmakers endless options to realize their visions. This often translates to many hours spent in post-production, replacing content to arrive at a decision. In the case of visual effects, assistant editors have to manually cut in numerous versions of shots when changes occur.

Assistant editor Rainer Standke has developed an application, XMiL Placer, to address the tedium of having to manually replace multiple iterations of visual effects shots in a Final Cut Pro sequence. The program automatically determines where newly arrived versions of effects need to go based on the original position of the clips in the timeline.

Placer works with a filter, VFXINFO (part of VFXTracker, created by picture editor Alan Edward Bell) that allows it to track visual effects shots. The VFXINFO filter is automatically installed when installing Placer. VFXINFO marks visual effects shots in a sequence via a Shot ID label, while Placer handles the placement of visual effects clips by matching the VFXINFO Shot ID with the corresponding clip name.

Launching the Workflow
The workflow begins by adding a VFXINFO filter to any shot in the sequence that will require an effect, which will be made in an outside facility. This filter is located under the Effects menu or in the Effects window in Final Cut Pro, Effects>Video Filters>Video>VFXINFO. Once the VFXINFO filter is placed on the clip, a Shot ID label (see Figure 1A) is added to the clip in order to track the clip’s position. The Visible option can be selected, allowing the Label and Shot ID information to be seen as a clip overlay (see Figure 1B). However, the visibility of the Shot ID in the image does not impact Placer’s ability to read the ID, so this feature can be disabled if so desired. Similarly, activating the Visible on Render option is not a requirement.

Figure 1: The VFXINFO filter allows a Shot ID to be added to the clip in order to track it. In this example, the selected clips (brown) have the VFXINFO filter added to them.

When the new visual effects clips have been imported into the project, these clips are selected along with the sequence in which they are to be placed, and an XML file is generated through the export menu option in Final Cut Pro, File>Export>XML.

At this point, Placer is launched and the user clicks on the Select Seq. XML button (see Figure 2A) in order to navigate to the previously generated XML file.

Once the file is selected, a variety of options can be enabled in Placer in order to increase the accuracy of clip placement in the sequence. Placer can be instructed to analyze all tracks in a sequence or selected tracks through the Use Clips from Seq. XML option (see Figure 2B). Under the Place New Shots option (see Figure 2C), one can select Shot ID matches of either all, or a set number of characters in the clip name, starting from the beginning or found anywhere within the clip name.

Figure 2: The XMiL Placer window provides numerous options to increase clip placement accuracy.

For example, a visual effects shot labeled XXSHOT1 would match a Shot ID label of SHOT1 if the “characters” value would be set to a value greater than 6 and the “anywhere” option was selected. This wouldn’t match if the “characters” value was set to a lesser number, or if “all” was selected instead or if “at start of” was chosen. These options address any number of variations in clip naming convention that might surface. Some discipline is required to maintain matching naming conventions, particularly on behalf of the effects house, in order to avoid having to re-label all of the incoming files.

Generating the New Project
At the bottom of the Placer window, the Send XML to Final Cut Pro option (see Figure 2E) is selected and the Go button is activated to generate a new Final Cut Pro project containing a new sequence with the spotted clips. The new sequence is labeled using the previous sequence’s title, combined with a date and time stamp reflecting when the sequence was created (see Figure 3A).

The newly imported clips are automatically placed on a new track above previously existing tracks in the sequence. Placer never overwrites clips in a sequence but will always position newer clips onto the next higher track (see Figure 3B). If there is more than one match for a shot, the effects clips will all be stacked on top of the original clip on separate tracks.

Figure 3: Placer creates a new project with a sequence from an XML file, combining original sequence information with the new visual effects clips.

All clips processed by Placer will be listed in the Placement Report window (see Figure 4), Window>Placement Report. The Placement Report readout displays a summary of placed clips and their respective position values in the timeline. Unmatched and unused new clips will be listed as well. This information can be saved to a text file for record keeping or troubleshooting.

Figure 4: The Placement Report window lists all of the clips processed by Placer. This report can be saved to a file or printed.

Placement accuracy can be further adjusted by setting different Shot Alignment (see Figure 5A) values based on the situation at hand. If, for example, the new visual effects shots are longer in duration than the original, one can select a “Proportional” alignment option in which the clip will be lined up, proportionally speaking, with the original version in the sequence. A “Center” value setting would be another option if the new clip is symmetrically similar to the previous clip.

Alignment is based on the handles of the clip, so that a clip with handles, split evenly between the head and tail ends, will line up with the original clip by referencing the center position. A clip with unequal handle lengths will be proportionally placed based on the offset handle lengths of the base clip. Other options include aligning the clips’ head or tail frames.

The Slate Frames (see Figure 5B) option accommodates clips, which have a slate or text graphic added to the head of the shot in order to identify it. The value entered into the Slate Frames field will cause Placer to exclude the slate frames from the handle length calculations.

Additional Options
Under ideal, controlled conditions, Placer can get very close to spotting visual effects clips to their base counterparts. However, the placement of visual effects shots should still be verified by visually matching the shots and making any necessary adjustments in Final Cut Pro.

Placer is designed to work in many different scenarios, with numerous options from which to choose (see Figure 5). Some of these options include:

Ignore Disabled VFXINFO Filters – This feature allows the users to skip any clip in which the added VFXINFO filter has been disabled.

Figure 5: Options for XMiL Placer.

Copy VFXINFO Filter from Base Clip to Placed Clip – With this option selected, the VFXINFO is transferred to the placed clip so that the Shot ID information and other VFXINFO settings are not lost from the base clip if it was replaced. In this case, the editor or assistant may not want to keep the previous iterations of the visual effects clips but rather only the recent editions.

Set Scale/Set Aspect Ratio to – This option is useful when working with mixed formats, so that if there’s any discrepancy between the size or aspect ratio of the new clips and the base version, the user can set a percentage and/or aspect ratio value to adjust the images to match. The expected values are similar to those found in the Motion panel in Final Cut Pro. These values are applied across the board, regardless of the actual size of the clips.
Re-Import Clips – Imports the new visual effects clips into the newly created project.

Report Placement in – Lists base clip name, sequence name, footage and video track information in Final Cut Pro under whatever column heading is selected in the pull-down menu.

Save Report in – The Placement Report information can be saved to a separate file, based on the time code, frame or footage count options selected in the pull-down menu. Enabling Open in Text Edit automatically opens the document in Text Edit after it’s created.

Disable/Enable All VFXINFO Filters – A global command to affect all VFXINFO filters in a sequence eliminating the need to manually turn on or off these filters one by one.

Place Clips on New Tracks – Copies base clips with VFXINFO filters to new tracks. This feature is helpful in isolating visual effects shots in the timeline.

Remove Original Clips – Removes the base clips from the sequence.

Create Review Sequence Clips – Generates a sequence which contains just the new visual effects clips with slates containing the name, date and time associated with the clip. Duration values of the slates and gap sizes can be entered in their respective fields.

Send XML to Final Cut Pro – “Beams” the XML data generated by Placer directly into Final Cut Pro without having to save an XML file to disk first and then manually importing it.

Export New Tracks Only – Generates a new sequence, which contains the new visual effects clips while omitting any of the original sequence clips.

Save New XML File in – Allows the XML information, which is sent to Final Cut Pro, to be saved to a separate XML file. This can be useful when troubleshooting the process.

In Closing…
Though Placer operates through a deceptively simple interface, it is designed to handle a variety of situations when dealing with editing and tracking visual effects. The full potential of this software is realized on visual effects-heavy shows, but any show that deals with visual effects changes will noticeably benefit.

To find out more about this software and other products available from, or under development by, Standke’s XMiL Workflow Tools, visit www.xmil.biz for more information. To learn more about VFXINFO or VFXTracker, go to www.handmadedigital.com, or www.vfxtracker.net.

Dieter Rozek is the Training Coordinator at the Guild’s West Coast office. He can be reached at training@editorsguild.com.

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