Joining operations
There are various operations available (illustrated as before and after):
Add—creates a new curve layer from the sum of the selected shape layers; the color of the lowest object is used.
Subtract—removes overlapped areas of the lowest object. All other selected objects are discarded.
Intersect—creates a new curve layer from the overlapping areas common to all selected shape layers.
Xor—merges selected shape layers into a curve layer with transparent area where filled regions overlap.
Divide—splits shape layer areas into separate curve layers; the curve layer from the intersecting area retains the color of the upper shape layer.
Cut away of a fully overlapping object from the object below (the residual object can be deleted).
Object being be split by one or more straight lines or curves.