Selecting With Lasso Tools
Photoshop CS6 Tutorial
How to Make a Selection with Lasso Tool in Photoshop
Photoshop includes three Lasso tools in the program. They are the Lasso tool, Polygon Lasso tool and Magnetic Lasso tool.
The Lasso tool is activated by click-dragging in the document in a free form fashion. Once you return to the starting point and release the mouse the selection is made.
The Polygon Lasso works well if your object is defined by a series of straight lines. Each time you click, another straight line is drawn.
The final tool is the Magnetic Lasso tool. It is great for following the edges of an object.
Open a new document in Photoshop (File > New). Set the size to 500 pixels by 500 pixels at 72 ppi. Set Background Contents to White.
Add a rectangle to the document with the Rectangle tool (u key). The tool options should be set to Shape layer.
Flatten the image by choosing Layer > Flatten Image.
Click the Lasso tool and click-drag to make a rough selection around the object. Release the mouse once you return to the starting point to finish the selection. This tool is great for rough selections. Once you are finished, press Cmd/d (PC - Ctrl/d) to deselect the object.
Select the Polygon Lasso tool and click a corner of the rectangle. Move the tool to the next corner and click a second time. Repeat the process two more times to finish the selection. Once you are finished, press Cmd/d (PC - Ctrl/d) to deselect the object.
Select the Magnetic Lasso tool and click a corner of the rectangle. Move the tool along the edge. Points are automatically dropped along the edge to pin the line down. You can also click to manually add points as you go. To delete any misplaced points, press the Delete key.
Magnetic Lasso Options
In the Magnetic Lasso tool options you can set the Contrast and Frequency values to better control the selection.
Constraining the Polygon Lasso Tool
By holding the Shift key, the Polygon Lasso tool is constrained to either horizontal, vertical or 45 degree movement.
Using the Combo Lasso Tool
There is a way to easily switch between all three Lasso tools on the fly. Start by choosing the Magnetic Lasso tool. Click a starting point, then click multiple times to begin making your selection.
Press and hold the Option key (PC - Alt key) and click the image. The tool changes to the Polygon Lasso tool. Click several times to continue outlining your object.
If you click the mouse and hold it in the down position, the tool switches to the Lasso tool. Release the Option key (PC - Alt key) and click once. It reverts back to the Magnetic Lasso tool.