So you want to round just one or two corners of a rectangle? Illustrator CS6 makes it easy to round all of them. Select a rectangle and choose Effect > Stylize > Round Corners. Set the Radius, click the OK button and you are good to go.
But what if you just want to round one or two corners? It can be done, though it is definitely more fussy. Here's one way to do it:
- Select a rectangle.
- Select the Scissors tool and click two opposing corners to separate the single rectangle into two independent right angles.
- Select one of the right angles, and choose Effect > Stylize > Round Corners to round one corner.
As a visual learner, I like to see a process to fully comprehend it, so in the image above, I moved one right angle off of the other. This is only so that the visual learners amongst you can see that the Scissors tool cuts the single shape into two right angles. It is not a necessary step.
- Repeat for the other right angle. (Note: Because I moved my right angles apart to illustrate the two independent shapes, I needed to re-align their top and left edges before continuing.)
- Finally, select both angles and combine them back into a single shape by choosing Object > Path > Join.