Importing an overlay

Unlike the underlay, an overlay may be added or removed from a project at any moment, even during the tracking process. The command that imports an overlay from file(s) is File|Import Overlay… It brings up an open file dialog that has a Force Static Overlay check box:

When it is unchecked the situation is the same as in underlay import. PatchMaker looks for all files with similar names and builds up an overlay sequence. Such an overlay is called live as it can vary in time. The duration of a live overlay is determined by the number of its frames. When a live overlay is imported, a confirmation message appears, indicating the number of frames imported:

Upon loading, the live overlay is positioned in the Trackline panel starting from the current frame. You can move it left or right to obtain the desired matching with the underlay.

If the name of an overlay frame selected in the dialog is unique (is the only one matching the file name template) or the Force Static Overlay option is checked, then a still overlay is generated. All its frames are identical and such an overlay can be extended to an arbitrary time range. If a still overlay was imported, the following message appears:

Importing an overlay from an AE project much resembles importing an underlay. Select the desired footage in the AE project window or the layer in the active composition window. Whenever this layer contains more than one frame, the item Upload as Live Overlay to PatchMaker in the AE Animation menu becomes available. If the layer contains a single frame, the item Upload as Still Overlay to PatchMaker becomes accessible. The same can also be done from PatchMaker, using the Import Live Overlay and Import Still Overlay items in the After Effects menu or the corresponding buttons in the After Effects^® panel:

When an overlay of any type is loaded, the match frame position is set to the current frame but you can move it manually to any other frame, including those outside the overlay time span. It makes sense, of course, to choose the match frame at the moment when the overlay is prepared.

If you are not sure what type of overlay was imported (still or live), then you can find it out by selecting the overlay in the Trackline panel with a mouse click and examining its Type property value in the property editor.