Magnetic Lasso

Lass

The Magnetic Lasso allows you to semi-automatically trace around objects in a photo to create a region. Once the region has been created you can copy or cut the object out, or apply an effect, or enhance the region.

Find the tool on the Photo Regions and Mask Tools flyout.

The tool is on by default - but you can toggle the auto-trace properties on or off using the toggle button on the InfoBar or by pressing T on your keyboard. Click the ? button next to the Magnetic Lasso toggle to bring up a step by step guide.

LassoBar

Magnetic Lasso InfoBar

Smoothing

Invert/clear outline

Show/hide outlines (Ctrl + H)

Toggle Lasso on/off (T)

Help guide

Tracing

To start - trace a dotted line around the edge of an object in your photo.

There are two ways to do this - Click and drag around the edge. Start on the edge you want to follow. As you drag around the item you'll see the dotted outline snapping to any nearby edge. You can press Shift to erase back along the path if things go wrong. Additionally pressing the space-bar will 'anchor a point' at the current pen position. Pressing T while dragging this way will toggle the magnetic snap off or on.

Alternatively - click on the edge - then click again a short distance further along, to trace the edge between the two click points. Continue clicking around the edge to trace around the object.

If at any point the dotted line misses the edge you wanted to follow, hit Backspace or Undo (Ctrl+Z) to undo the last click point. Then zoom in and click closer to the last point, on the edge you want the trace to follow. You will need to move in smaller steps along any parts of the edge that are less clearly defined, but where the edge is clear against the background you can move along the edge in much bigger steps.

For both methods, pressing the Alt key while clicking or dragging will draw a straight line section from the last point to the current position. Pressing T will toggle the magnetic aspect off or on. With no Magnetic snap, then dragging acts exactly drawing with the Freehand tool. Clicking with no magnet snap will just add a straight line segment to the current point.

Following the photo edge

Sometimes you may want the outline to follow the edge of the photo. To do this, click just outside the photo edge.

Finishing

When you get back close to where you started, click on the start point again to complete a closed outline (the mouse pointer will change to show a + sign when you are over the start point) .

Once you have a complete closed outline, you can now copy (Ctrl + C), cut (Ctrl + X) or delete the selected part of the photo. You'll notice that as you perform the operation the Selector Tool is automatically selected.

Feathering

Once you have cut out an object, you can usually improve the edges by applying a small amount of feathering using the feather control on the top InfoBar.

Magnetic Lasso works well on images where there is a high contrast between the object you want to cut out and its background. Also if you have an image with lots of fine detail - like hair or fur for example then you will get a better result if you use the Background Erase feature instead.

 

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