Join Mordy Golding for an in-depth discussion in this video Understanding paths, part of Illustrator CS4 Essential Training.
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So now we understand the difference between vector-based graphics and pixel-based or raster-based graphics. So now let's take a look at more of an understanding of what these vector graphics are, what makes them tick, what are they made of. So you'll notice we're here in this file, and by the way, if you have access to the exercise files, you can follow along by opening up the file called understanding_paths, which you'll find in the Chapter 01 folder. So I have basically these four charts that I have created. I have put these graphics onto them and we're kind of just getting a better understanding of what each of these graphics are now. From a vector standpoint, there are really two classifications or two types of paths; there are what we refer to as open paths, which are the two that we see at the top of my screen right here. Open paths have no enclosed area. Then you have closed paths, which basically have an enclosed area here as well.
As we learn more about Illustrator, there will be times where there are differences between open and closed paths, especially when we talk about the attributes that those particular paths have. Now a path itself-- let's say we take a very simple case, a straight line. Basically, I have here is two anchor points, one anchor point here, which defines start point, and one anchor point, which determines the end point, and basically when you are working with Illustrator by plotting the anchor points here, this path is automatically created or connecting the two. By default, anchor points themselves are connected by straight lines.
The shortest distance between two points of a straight line; that's kind of what you have there. As we'll learn more about anchor points, we'll talk more about the Pen tool as we learn later on. Other things inside of Illustrator. But just as a basic idea of what's to come, there are also different types of anchor points. Right now this anchor point is what we refer to is a corner anchor point, meaning that the line that emanates or that comes out of that anchor point is a straight line. As you notice over here, this anchor point has a curve line that comes out of it, and that particular anchor point is referred to as a smooth anchor point. So you have corner anchor points and smooth anchor points. We'll talk about the classifications of those as well. But again, that's how you define these particular shapes here.
Now each point that you have has a coordinate on that chart, and obviously when that chart gets enlarged or you make your file size bigger so on and so forth, Illustrator simply remaps that particular point on a particular chart and then draws that new path again. If you look over here at a rectangle, for example, a rectangle is made up of four anchor points, one, two, three and four; they are corner anchor points, which means that they are all connected with straight lines, and that's what creates the rectangle. It's important to note that an oval, circle or any of the kind of shape like this has also four anchor points. But the only difference is that the anchor points are positioned differently inside of the corners to position the top, bottom, left and right.
You'll notice that the lines that connect these anchor points are curved. So let's first focus on this one over here and understand what that means. I have an anchor point but Illustrator also has this curve path that comes out of it. Now what's making that path curved? Remember, the actual coordinates of this anchor point and this anchor point are the exact same coordinates of this anchor point and this one. So what's making this line straight is, in fact, these are corner anchor points. These are smooth anchor points and that allows it to be a curve. Now what controls that curve? We'll notice there is a line over here that's kind of coming out here with little dot. This is what we call a Control Handle.
The Control Handle is what determines that particular curve. Notice that the path itself over here follows that curve. As we'll start to learn inside of Illustrator, I can start to manipulate these control handles in the path, kind of is drawn to almost like a magnet . As I would for example take this particular Control Handle and pull it up higher this part of the curve would also kind of be attracted and move in that particular direction. That's really what's making this particular overwork as well. I have a regular anchor point here, but this Control Handle is pulling out the curve in this direction. At the same time, the Control Handle from this curve from this particular anchor point here is making the curve appear in that particular way.
Now, when you're talking about Vector Graphics as well and you started having control handles, there are coordinates for those control handles as well, which memorize where that part goes. Now, it's important to realize by the way. When I print my files I don't really see the anchor points, I just see the path itself. And again, we'll talk more about how that works, but for now I just realize that these are ways that I can actually work with and edit these particular paths. But the way that I control them or what we call the appearance of these particular paths is what we'll cover now in the next video.
- Making efficient use of the Illustrator interface
- Creating text on a path
- Using the Magic Wand and Lasso selection tools
- Working with a pressure-sensitive tablet
- Applying 3D extrusions and resolves
- Converting images to vectors with Live Trace
- Exporting files for use in Photoshop, Flash, and other applications