Mesh

In Adobe® Illustrator® CS2, gradients allow you to fill an object with gradations of color that blend into each other. Although these gradients are certainly useful, they are limited from a creative standpoint because they can only be used in linear or radial forms. In Illustrator 8, Adobe introduced a radical new feature called Gradient Mesh: an incredible tool that allows you to create gradients in any shape. The results are painterly effects that look as if they had come right out of Adobe Photoshop®—yet they are all in vector form using the gradient mesh feature. And if you can achieve the appearance you’re looking for while keeping your file in vector form, you can keep your art completely scalable and editable throughout the design process. For example, changing one color in a gradient mesh is far easier than trying to replace a color that’s used in a Photoshop file.

However, the Gradient Mesh tool isn’t the easiest feature to understand. Many people would like to use the feature, but they can’t figure out any consistent way to explain its behavior. Hopefully, this tutorial will help you understand what a gradient mesh is and how it works.

Before you learn how gradients are applied, let’s talk about what a mesh is. A mesh is a grid made up of multiple anchor points, called mesh points.

You can pull or adjust each of these anchor points to control the shape of the mesh. A mesh is really a special kind of construct or object in Illustrator, and it does not act like a regular path does. Mesh objects do not have normal Fill or Stroke attributes and can’t display certain kinds of Live Effects. Rather, you use mesh objects to contain two kinds of attributes in Illustrator: Gradients and Envelopes. When you’re using a mesh to define a gradient, each mesh point determines a color stop and the way in which that color blends into other colors.

Create and edit a Gradient Mesh Object

To create a Gradient Mesh object, choose the Mesh tool from the Toolbox and click any vector path in your document. You don’t draw Gradient Mesh objects from scratch in Illustrator; you convert existing vector shapes to mesh objects. Each click with the Mesh tool adds additional mesh points to the mesh object. You’ll also notice that as you add mesh points to an object, the paths that connect the mesh points match the contours of the object.

Once you have mesh points defined, you can switch to the Direct Selection tool and select each individual mesh point to adjust its position and its direction handles.

With a mesh point selected, you can choose a color from the Control, Swatches, or Color palette to define the color for that point. Each mesh point can contain only one color. Each mesh point’s direction handles and paths define how its color blends with other colors from other mesh points.

As needed, you can switch back to the Mesh tool and click to add additional mesh points.

You can also create a gradient mesh from an existing vector object. With the object selected, choose Object > Create Gradient Mesh. You can then choose how many rows or columns you want in the mesh, and if the object is filled with a color, you can specify a highlight towards the center or the edge of the object. Once the gradient mesh is created, you can continue to tweak it using the methods mentioned previously.

Note: If you converted a path to a mesh object and then want to get the path back, you can select the mesh object and use the Offset Path function with a setting of 0. This action creates a new path that you can edit and color as you wish.

http://www.adobe.com/designcenter/tutorials/gradientmesh/

Using Illustrator’s Gradient Mesh feature you can make complex fills that have amazing realism. I have seen incredible examples of this, like the flower that was the logo for Illustrator CS and of course, Venus, who graced the Illustrator box and the top of the toolbox for many versions. So how do you use this wonderful tool? The best way to learn it is to jump right in and experiment with it.

To experiment with the tool, draw a simple shape like this ellipse. Use a solid color fill for this exercise; the Gradient Mesh tool will not work with pattern fills, and to keep a gradient fill you already have on an object there is an extra step. (Select the object, and go to Object > Expand and choose Fill. Then create the gradient mesh.) You can have a stroke, but the Gradient Mesh tool will remove it. One thing to remember when using the Gradient Mesh tool is that when you use this tool on an object, it converts it to a Gradient Mesh Object. Editing the points of the Gradient Mesh can also change the shape of the object as well as the color.

Make sure the fill color is the active chip in the toolbox or the Gradient Mesh tool will have no effect. Activate the Gradient Mesh tool in the toolbox and click once on the ellipse. I clicked in the center just to show how much difference this tool can make even with one point of color added. The center point is selected; just use the color palette to change the color, and the color of the point changes, and shades into the rest of the ellipse.

Add points clicking with the Gradient Mesh tool, and change the color as desired with the color palette.

Points can be moved and edited using the direct selection tool or the Gradient Mesh tool, and the colors are redistributed on the mesh automatically. If you are using the Gradient Mesh tool, make sure you are exactly on the point you want to move, or the tool will add another point. Select multiple points to recolor or move by holding the shift key as you click on the point with the Direct Selection tool. You can also use the arrow keys to precisely move selected points.

You can set up the mesh with as many points as you wish before coloring too. Go to Objects > Create Gradient Mesh and set the desired number of points across and down. For an automatic start to the shading, choose whether you want the mesh to shade to the center or to the outside. If you choose Flat, there will be points but no shading until you change the color of the points. Even though you can do it this way, I rarely do as I find it doesn’t always place the points where I want them, so I prefer to add them myself with the Gradient Mesh tool.

You can use also recolor clipart. There is some clipart already in Illustrator format in the Goodies folder on your Illustrator CD. Inside the Goodies folder is a folder called Clip Art and Stock Photos. Find a piece of clipart you like and start experimenting.

Tracing clipart works as well. Your initial drawing can be very rough, as mentioned before. Not only doesn’t it have to be perfect, the lines can overlap. Use Live Paint to fill the parts of the drawing with the base colors, and then use the Gradient Mesh tool to add the shading. After you start to use the mesh tool, the strokes are removed, and you’ll be able to move individual points to close any gaps.

You could also use Illustrator’s Live Trace feature to trace a photo and use the Gradient Mesh tool for shading. This is an extremely powerful tool that is also a lot of fun to use!