On

Click On when the command prompt requests a point to use this modifier.

ON locks to a point mathematically on any entity selected within the cursor's pick box. As with all modifiers, you must first select a drawing or editing command. The prompt reads "Select reference entity:". Select a point on the entity you want to lock to.

The ON modifier will supersede any Snap or Attach settings.

ON tip
ON is used to join rivers to coastlines as in the following example. Imagine that you are in the middle of drawing a river. It is approaching the coast:

Now click On( ) and you will see a square cursor. Select a point on the coastline.

Your river ends up looking like this:

To lock to a series of points on other entities, use Attach instead.

Text equivalent: ON (or press function key F9)