This is really two powerful tools in one, and can be used to
perform hard-edged vector erasing of shapes and photos, or soft erasing.
Hard Erase
When used with a hard edge, it’s a fast and direct way of
adjusting the vector outline of a shape inwards. If you stroke around the edge
of a shape with your mouse, it just moves the outline inwards.
Dragging a hard-edge erase stroke completely across an
object will cut it in two and create two separate objects. If you click and
hold (i.e. don’t perform a brush stroke), it will simply cut a hole in the
shape.
Soft Erase
You also have a soft erase option; strokes over any object
(which can be any shape, text or photo) will erase, ie make transparent, the
brush-stroked area. The softness control adjusts how soft the edge of the brush
stroke is.
Non-destructive
editing
One of the great things about this soft erase feature is
that it’s not destructive, that is it doesn’t change the underlying erased
shape or photo at all, unlike most other photo editing programs.
This has some important benefits: not only can change your
mind at any point and re-adjust the erase, but you can also un-erase and even
remove all the erase strokes and recover the original, unmodified shape, text
or photo. What’s more you can, for example, apply a soft erase across some
text, or perhaps a 3D extruded shape, and then still edit that text, or adjust
the 3D extrude, after the erase has been applied.