Читать книгу SketchUp For Dummies - Mark Harrison - Страница 37

Edges are lines. You can use lots of tools to draw them, erase them, move them, hide them, and even stretch them. Here are some things you ought to know about SketchUp edges:

 Edges are always straight. Not only is everything in your SketchUp model made up of edges, but also, all those edges are perfectly straight. Even arcs and circles are made of small straight-line segments, as shown in Figure 3-2.

 Edges don’t have a thickness. This one’s a little tricky to get your head around. You never have to worry about how thick the edges in your model are because that’s not how SketchUp works. Depending on how you choose to display your model, your edges may look like they have different thicknesses, but your edges themselves don’t have a built-in thickness.

 Just because you can’t see the edges doesn’t mean they’re not there. Edges can be hidden so that you can’t see them; doing so is a popular way to make certain forms. Take a look at Figure 3-3. On the left is a model that looks rounded. On the right, the hidden edges are visible as dashed lines. See how even surfaces that look smoothly curved are made of straight edges?

FIGURE 3-2: Even curved lines are made up of straight edges.

FIGURE 3-3: Even organic shapes and curvy forms are made up of straight edges.