New Bristle Brush and Other Brush Improvements
The Bristle brush makes its debut in Illustrator CS5, allowing you to paint with vectors that resemble real-world brushstrokes (see Figure 3). You can work with this new brush the way you'd work with watercolors and oils, but with the scalability and editability of vector art.
Figure 3 What makes the Bristle Brush unique are bristle characteristics such as stiffness, length, bristle density, and moreall of which can be controlled before or after you paint.
If you use a pen tablet, such as the Wacom 6D pen, painting strokes automatically responds to pressure, bearing, and tilt with 360-degree barrel rotation. Illustrator CS5 also provides an accurate brush preview, adding to the lifelike capabilities of the brush.
You can choose areas of the brush stroke to be resized in proportion (see Figure 4). For example, say you apply a banner art brush to a semicircular path. In previous versions, the banner would be stretched across the path, typically leading to distortion. In CS5, you can specify in the brush definition that (for instance) detailed, curly ends shouldn't stretch, and only the middle of a banner should elongate. In addition, you can apply art and pattern brushes to a path at tight bends or corners to fill points properly where joins occur.
Figure 4 In addition to the creative expression that the Bristle Brush now allows, you can define the scaling for art and pattern brushes along a path.