When you draw shapes that overlap other shapes, the shape creation features such as splitting, combining, or automatic closing are available depending on the configuration of the tool options.
You can split shapes using the Polygonal Shape Creation tool (S). When the first and last vertex are snapped to an edge or vertex of the same shape, and the whole line is contained in this face, it is automatically split into two parts.*
To create a shape that closes along the edges of connected shapes, click the Automatic Closing toggle key in the Polygonal Shape Creation tool options . Ensure that the Shapes option is enabled under Snapping. Snap the first point to an edge or vertex of a shape and continue to the last point in which you snap to an edge or vertex that is indirectly or directly connected.*
To automatically close shapes, ensure that the toggle key is on before placing the first point.
To combine shapes into one shape, click any of the shape creation tools and draw a shape that snaps to an existing shape. Ensure that the Shapes option is enabled under Snapping in the shape creation tool options.*
Force New Shape
The Force New Shape option forces a new shape to be created, including when drawing intersecting shapes. Click the Force New Shape toggle key in the tool options of any of the shape creation tools.
*This option is unavailable when Force New Shape is enabled.