Creating Views > Adding Overlays > About Overlays
  
About Overlays
An overlay is an image that represents manufacturing output data.
Use an overlay to compare manufacturing output data by placing the overlay over the corresponding PCB layout design. You can set the format, unit, polarity, placement, and scale for files without embedded settings. Gerber RS-274X file contains settings for placement, format, scale, and other parameters, while a Gerber RS-274D file does not. Then, load an overlay to a design in either of these ways:
Create an overlay from an external file.
Open an overlay viewable contained in the PVS or PVZ file.
Creo View ECAD contains commands for aligning and rotating the overlay to the design.
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Rotating an overlay before performing an alignment operation produces the best result.
After you have placed an overlay on a design, you can perform the actions listed below:
View the resulting overlaps and add markup.
Invert the order of the overlay and one or more design layers to check that they correspond as intended.
Enable or disable the display of the overlay’s tooltips.
Save the overlay as an annotation set.
Open a Gerber file in a new view.
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You can load more than one overlay to a design, but you can only turn on the visibility of one overlay at a time.
Loaded overlays appear under Annotations on the Color and Visibility pane of the upper data panel.
You can also open a Gerber overlay in a new view. By default, the visibility of all its sublayers is on. A Gerber overlay opened in a new view has three or four sublayers in Creo View, depending on the file’s data:
Fills
Flashes
Lines
Outline—Included if the file has a photoplot outline