You can take a snapshot of a blade design so that, as you modify
the current design, you can easily compare it against the snapshot
to visualize the changes you have made. When the FlowPath, Blade,
and Splitter features have been successfully generated, you can click Create snapshot
to take a snapshot, or to update
the snapshot, of the current blade design.
The snapshot also appears in the following views:
Model View
The snapshot appears in the 3D Viewer as a transparent (by default) blade set.
Until you change the blade geometry, the snapshot will coincide with the blade in the Model View. To see the snapshot by itself, suppress the display of the blade geometry (for example, by clicking Display Model
to hide the geometry).Angle view
Thickness view
Blade to Blade view
Click Comparison On/Off 
to toggle the visibility of the snapshot in all
views that can display a snapshot. While comparison mode is on, you
cannot update or clear the snapshot.
To clear the snapshot, click Clean snapshot 
. Deleting the snapshot has a (usually minor)
benefit; it reduces the disk space required to save your case.
You can control display options for the snapshot by clicking Comparison display option 
and making changes in the details view.
Blade comparison is demonstrated in Tutorial 1: Blade Editing With Emphasis On Sketches, Layers, and Blade Comparison.