2012

Snaps to a point object, dimension definition point, or dimension text origin.
Quadrant
Snaps to a quadrant point of an arc, circle, ellipse, or elliptical arc.
Intersection
Snaps to the intersection of an arc, circle, ellipse, elliptical arc, line, multiline,
polyline, ray, region, spline, or xline. Extended Intersection is not available
as a running object snap.
NOTE You might get varying results if you have both the Intersection and Apparent
Intersection running object snaps turned on at the same time.
Intersection and Extended Intersection do not work with edges or corners of
3D solids.
Extension
Causes a temporary extension line or arc to be displayed when you pass the
cursor over the endpoint of objects, so you can specify points on the extension.
Drafting Settings Dialog Box | 677