How to Use the Polygonal Lasso Tool in Photoshop

Finding the Polygonal Lasso Tool

Click and hold the Lasso Tool and you’ll find the Polygonal Lasso nested underneath it. The shortcut for the whole Lasso group is L, so hold Shift and press L to cycle to the polygonal version. That Shift-plus-shortcut trick reaches every nested tool in Photoshop.

Click Around the Straight Edges with the Polygonal Lasso Tool

Every Polygonal Lasso Tool click drops a point, and Photoshop draws a straight segment to the next one. Zoom in with Ctrl/Cmd + plus, click along the edge of the building, and make each segment as long as the real edge: one point at each corner is all you need. When you come back to the start you’ll see a small circle next to the cursor; click there, or just press Enter, to close the selection.

Fix Mistakes Without Starting Over

Put a Polygonal Lasso Tool point in the wrong place and Backspace (Delete) removes the last one. Keep pressing and it walks back through your points one at a time, so you can retreat to the last good corner and carry on. Escape abandons the selection entirely.

Add, Subtract, and Intersect

Hold Shift (or click the Add icon in the options bar) to add a new polygon to the existing selection. Hold Alt/Option to subtract, which is how Aaron cleans up an accidental bump along the roofline. The Intersect mode keeps only the overlap between the old selection and the new one.

Use the Selection to Recolor the Sky

With the building selected by the Polygonal Lasso Tool, add a Hue/Saturation adjustment layer and the selection becomes its mask automatically (Alt/Option-click the mask to see it). Turn on Colorize and push toward blue, and you’ll notice the building changes instead of the sky, so click the mask and press Ctrl/Cmd + I to invert it. Now the saturation and lightness sliders only touch the sky, and the building stays exactly as shot.

Switch to the Freehand Lasso Mid-Selection

Hold Alt/Option and drag while using the Polygonal Lasso and it temporarily becomes the regular Lasso, so you can trace a curved object and go back to straight lines the moment you release. The reverse is also true: hold Alt/Option in the regular Lasso and it snaps to straight segments. The two tools are effectively one.

Feather the Edge

Polygonal selections are hard-edged by default. Set Feather in the options bar before you draw, say 20 pixels, and Edit > Fill with white shows a soft, cloud-like edge instead of a crisp one.

Quick Reference

• Shift + L cycles to the Polygonal Lasso Tool.
• Click to place points; Enter closes the selection; Backspace removes the last point.
• Shift adds, Alt / Option subtracts, Intersect keeps the overlap.
• Alt / Option + drag switches to the freehand Lasso and back.
• Ctrl / Cmd + I on a layer mask inverts it.
• Feather in the options bar softens the edge before you draw.