There are three basic types of sketch icons:
For
a normal sketch.
For a Sketch Instance.
For a Sketch Projection.
Along with the basic icon there is also a status symbol that appears with it to indicate its visibility mode.
Always Visible: Sketch is always
visible, even when viewing another plane.
Normal Visibility: Will be visible
if its base plane is visible. This is the default visibility setting.
Hidden: Only displayed when it is selected
in the Tree Outline, or is the active sketch while
in sketching mode. While hidden, its edges will not be used for Auto Constraints or dimensions, unless it is the active
sketch.
Other Sketches and Planes topics: