Using the Lasso, Polygonal Lasso, and Magnetic Lasso Tools

The lasso and polygonal lasso tools let you draw both straight-edged and freehand segments of a selection border. With the magnetic lasso tool (Photoshop), the border snaps to the edges of defined areas in the image.

To use the lasso tool:

1. Select the lasso tool, and select options.
2. Drag to draw a freehand selection border.
3. To draw a straight-edged selection border, hold down Alt (Windows) or Option (Mac OS), and click where segments should begin and end. You can switch between drawing freehand and straight-edged segments.
4. To erase recently drawn segments, hold down the Delete key until you’ve erased the fastening points for the desired segment.
5. To close the selection border, release the mouse without holding down Alt (Windows) or Option (Mac OS).

To use the polygonal lasso tool:

1. Select the polygonal lasso tool, and select options.
2. Click in the image to set the starting point.
3. To draw a straight segment, position the pointer where you want the first straight segment to end, and click. Continue clicking to set endpoints for subsequent segments.
4. To draw a freehand segment, hold down Alt (Windows) or Option (Mac OS), and drag. When finished, release Alt or Option and the mouse button.
5. To erase recently drawn straight segments, press the Delete key.
6. Close the selection border:

To use the magnetic lasso tool (Photoshop):

1. Select the magnetic lasso tool, and select options.
2. Click in the image to set the first fastening point. Fastening points anchor the selection border in place.
3. To draw a freehand segment, move the pointer along the edge you want to trace. (You can also drag with the mouse button depressed.) The most recent segment of the selection border remains active. As you move the pointer, the active segment snaps to the strongest edge in the image, based on the detection Width set in the options bar. Periodically, the magnetic lasso tool adds fastening points to the selection border to anchor previous segments.
4. If the border doesn’t snap to the desired edge, click once to add a fastening point manually. Continue to trace the edge, and add fastening points as needed.
5. To activate the lasso tool, hold down Alt (Windows) or Option (Mac OS), and drag with the mouse button depressed.
6. To activate the polygonal lasso tool, hold down Alt (Windows) or Option (Mac OS), and click.
7. To erase recently drawn segments and fastening points, press the Delete key until you've erased the fastening points for the desired segment.
8. Close the selection border.