Apr 27 2009
Adobe Illustrator Tip– Simple Gears using Pathfinder and the Star tool.
By: Rick Yaeger
One the features I find myself using the most in Adobe Illustrator is its Pathfinder tools. This week I’m going to show you a one of the ways you can use the Pathfinder. I will also be making use of the Star tool in a way that you may not have thought of before — to make gears.
Why would you want to make gears? I don’t know. Maybe you need to need to make some cold war era industrial looking propaganda posters. Maybe you never got over that gear fad that caught on in the early 90′s. Who knows. It’s not important. This tutorial is more about showing a few techniques that you might find useful in other situations while giving you a simple example of those techniques in action.
Step 1: Establishing a center point.
Easy enough. Make sure the rulers are visible (Command-R if they are not) and drag one vertical and one horizontal guide into the approximate middle of the page.
Step 2: Draw a star.
First, choose the Star tool from the Tools palette. Set your stroke color to black and your fill color to "none". Place your cursor on the guides where they intersect, click and hold the mouse button as you drag away from the center point. You will notice that the Star tool chooses the number of points for the star without asking you. Press the up arrow to increase the number of points and the down arrow to decrease — remember to keep that mouse button held. I have chosen to go with a ten pointed star. I find that stars of six or more points seem to make better looking gears. I also find that stars with longer spikes are more conducive to gear making. In order to lengthen the spikes on your star, drag the mouse somewhat close to the center point so that the inner points of the star are closer to each other, then hold down the Command key and drag the cursor away from the center point thus lengthening the spikes on your star. Don’t go too far with lengthening the spikes — we’re making a gear, not a spur.
Step 3: Circles.
Now you’ll need to choose the Circle / Ellipse tool. Again place your cursor on the guides where they intersect, but hold down the Option and Shift keys and click and hold the mouse button as you drag away from the center point — this will draw perfect circles dead center. You need to make three circles: one that should fit inside your star shape without overlapping any of the lines that make the star, and two more that should end up outside the inner points but inside the outer points while not being too close to each other. Confused? Hopefully this diagram will help.
Step 4: The hard part is over… on to the Pathfinder!
Under the Window Menu, chose "Show Pathfinder." Select your creation and click the Divide button in the Pathfinder window. You have just made your four shapes into more than a dozen that are Grouped. Go ahead and Ungroup them (Command-Shift-G).
Next you will need to select and delete each and every one of those shapes that was created between the spikes of your star and your two larger circles (see the diagram below).
Are you seeing it yet? Don’t worry, you will. Now delete the tips of the spikes and the innermost circle. (See diagram) You may become confused while trying to delete the innermost circle since once you delete it, the outline will remain. Don’t worry, that is exactly what is supposed to happen.
Step 5: Almost there
What you are left with might look somewhat gear-like — it had better because we are pretty much done. Select the entire creation and click the "Add to shape area" button. Then click the "Expand" button. (If you are using a version of Adobe Illustrator that predates this version of the Pathfinder, simply click the "Unite" button)
Now just switch your fill color to black and your stroke color to none and marvel at your creation. If your creation isn’t that marvelous, marvel at my creation for a while and then try again. There are so many variables involved in this procedure that the possibilities are nearly endless. Unfortunately, with that many possibilities, the likelihood of creating a goofy looking gear is pretty high. Keep trying.