Manipulating Overlays
Overlays can be used to create abstract shapes required to outline an area of interest. This includes the following:
- Combine (unite) different overlays together
- Subtract overlays from one another
- Intersect two overlays
Combining Overlays - into a single overlay
In this option the area that overlaps between the two overlays is generated. This is shown below for two ellipses
- Use the overlay options to create the required shapes.
- Select the overlays (Control + A selects all, select each overlay by pressing Control and the left mouse button).
- Select Unite from the overlay options drop-down list (two or more overlays must be selected for Unite to work).
- The two overlays are combined into one complex shape (in this example two ellipses).
Subtract Overlay - subtract one overlapping overlay from another
In this option the area that overlaps between the two overlays is generated. This is shown below for two simple rectangular overlays.
- Use the overlay options to create the required shapes.
- Select one overlay- the area that overlaps the other overlay will be subtracted from the non-selected overlay.
- Select Subtract from the overlay options drop-down list (two or more overlays must be selected for Subtract to work).
- The overlapping area between the two overlays is created (in this example the overlapping section between the two rectangles has been subtracted from the non-selected overlay).
Intersect Overlay - select the intersection between two overlapping overlays
In this option the area that overlaps between the two overlays is generated. This is shown below for two simple rectangular overlays.
- Use the overlay options to create the required shapes.
- Select the overlays (Control + A selects all, select each overlay by pressing Control and the left mouse button).
- Select Intersect from the overlay options drop-down list (two or more overlays must be selected for Intersect to work).
- The overlapping area between the two overlays is created (in this example the overlapping section between the two rectangles, the remainder of both overlays is deleted).