Use the MAP Trim Tool to quickly trim lines to a specified line. There are two methods to trim lines:
1.Click lines individually to trim.
2.Click and slowly drag across multiple lines to trim.
The MAP Trim Tool works on all lines (paths and compound paths).
The MAP Trim Tool doesn't work on closed paths. As a workaround, if necessary, expand a closed path first, then trim.
Using the MAP Trim Tool
Before any lines can be trimmed, it is necessary to select a "trim-to" line; a line where any intersecting lines are trimmed to.
Step 1: Select the trim-to line.
Individual Line Trim
On the Adobe Illustrator Tools toolbar, click the MAP Trim Tool button. Click a line that intersects the trim-to line; the intersected line is highlighted temporarily and then removed.
Step 2A: Click a line to trim it to the selected trim-to line.
Result 2A: Individual line is trimmed.
Click and Drag to Trim
On the Adobe Illustrator Tools toolbar, click the MAP Trim Tool button. Click and slowly drag the cursor across lines that intersect the trim-to line. Lines that are eligible to be trimmed are highlighted. Release the mouse button to complete the trim and the intersecting lines will be removed.
Step 2B (multiple line trim): Click and slowly drag across multiple lines to select them for trimming.
Result 2B: Lines are trimmed to the trim line.
To quickly select other lines while the MAP Trim Tool is enabled, hold the Ctrl or Command (Mac) key to change to the Selection Tool. To select multiple lines, hold both Ctrl (or Command) and Shift keys.
It may be useful to lock other layers when using the MAP Trim Tool.
Lines that are split in two using the MAP Trim Tool are turned into a compound path.