At the risk of sounding like Mr Miyagi, a house will only ever be as sturdy as the foundations on which it is built. Or, putting it another way, you'll end up with a pretty disappointing interface if you don't spend a little time getting the underlying shapes as smooth as possible. Of course, you can go through the lengthy and often very frustrating process of manually removing 'jaggies' at the end of the project, but you can save yourself lots of trouble letting Photoshop do most of the work for you at the beginning instead. Just follow these four easy steps to smoother work...
Step 1: Create a new 500px by 500px document with a white background. Create a new layer called shape. Using the Rectangular Marquee Tool, Elliptical Marquee Tool, and Polygon Lasso Tool, draw some complex shapes in this new layer and use the Edit > Fill command from the menu to fill them with black. Feel free to experiment here - I created the shape on the left using nothing but circles and rectangles. Don't worry about the sharp edges - they'll all be gone when we're finished.
Step 2: When you are happy with your shape, press CTRL and click on the shape layer in the layers palette to make it the active selection. Now go into the channels palette (you can get there by clicking on a tab above the layers palette). Click on the create new channel button to make a new channel & call it alpha. With the selection still active, Edit > Fill the shape with white and then Select > Deselect. Now run the Filter > Blur > Gaussian Blur filter with a setting of 5 to 10, depending on how rounded you want the final shape.
Step 3: With the channels palette still active, click on Image > Adjust > Levels from the menu to open up a panel very similar to the one on the left. Drag the two outer triangles towards the centre until your shape looks nice and smooth. Don't overdo it, though, or you'll get jaggies. Once you are happy with your shape, hold CTRL and click on the alpha channel to create a new selection.
Step 4: Go back to the layers palette and create a new transparent layer. Select it and then fill the shape selection with black using the Edit > Fill menu command. Delete the old shape layer or make it invisible - you don't need it anymore. And that's it - you now have a nice smooth shape which you can bevel, colour, and manipulate however you want! Experiment lots with the principles of this tutorial and you'll go a long way to understanding the whole basis of interface design. Have fun!
