I’m heading over to the Modify panel today to talk about two related buttons there – Break and Break At Point.
The regular Break command inserts a gap between two points on an object, splitting it into two new objects.
By default, the click you use to select the object to be broken is the same as the click that defines the first point of the break.
You can either accept that first point (which may or may not be accurate enough) and click again to specify the second point, or enter F to pick a new, more precise first point and then the second point.
Break points don’t have to be actually on the object. If you click nearby instead, that point is projected onto the object. Of course, you can always use object snaps to help you be more precise.
Here’s an arc, before and after being broken:
It is also possible to simply split an object into two, without creating a gap. One way is to pick the first point as usual, then enter “@” when prompted for the second point. This reuses the coordinates of the last pick.
Or, you can use the “Break At Point” button found next to Break on the Modify panel. This command – actually a macro – does the work of setting the “first” and “@” options for you, so you only have to pick one point on the object to create the split.
Here’s the arc again, this time split with the “Break At Point” function:
(I had to show you the arc selected here, or you might not have believed me that I actually broke it!)