Chapter 22: From Drawings to Models 493

Getting Your 3D Bearings

The first challenge in 3D modeling is being able to see your three-dimensional model on a two-dimensional computer screen. The normal model space view on the Model tab in the drawing area shows a single, projected 2D view of your model — the top-down, “plan” view by default.

AutoCAD provides two model space capabilities that enable you to escape this visual flatland:

With viewports, you can carve the model space drawing area into smaller rectangular areas, each of which shows a different view of the model.

With viewpoints, you can change the point in 3D space from which you look at the model. By setting a different viewpoint in each viewport, you can look at several sides of your model at the same time. It’s like looking at one of Picasso’s cubist paintings, only what you see is more orderly.

No matter how much or how little 3D modeling you’re thinking about doing, it’s well worth your while to set up a template. (We fill you in on drawing templates in Chapter 4.) If you’ve ever started a new drawing, you’re probably aware that AutoCAD already comes with a template for 3D modeling named acad3d.dwt (or acadiso3D.dwt for the metrically inclined). This is fine as far as it goes, but it only shows you a single view of your model. The next section explains how to improve on this template.

Creating a better 3D template

Model space viewports enable you to see several views of your model at one time, each from a different viewpoint. For this reason, model space viewports are especially useful when you’re creating and editing objects in 3D. As you draw and edit, the different views help ensure that you’re picking points that are located correctly in 3D space.

Chapter 5 discusses viewports in paper space, which are useful for creating layouts for use in plots and presentations in both 2D and 3D. Model space viewports, cousins of paper viewports, are less flexible but simpler, and are a great help in constructing 3D models.

Model space viewports divide the screen into separate rectangles with no gaps between them. Unlike paper space viewports, you can’t move, stretch, or overlap them. You can’t plot multiple model space viewports (that’s what paper space is for). And, unlike the situation in layouts, a layer that’s visible in one model space viewport always is visible in all of them.

www.it-ebooks.info

494 Part V: On a 3D Spree

You may hear or read references to tiled viewports, which is just another name for model space viewports. Tiled refers to the way in which model space viewports always fill the drawing area, with no gaps and no overlapping allowed. Conversely, paper space viewports are sometimes called floating viewports because you can move them around, leave gaps between them, and overlap them.

One of the best new features introduced in AutoCAD 2012 goes by the somewhat obscure title of in-canvas viewport controls. Those little text labels that you may have noticed at the top-left corner of the graphics area (see Figure 22-1, for example) are clickable controls that let you set the visual style and the view. What’s especially nifty is that double-clicking the plus or minus sign toggles the drawing area between multiple tiled viewports already configured for 3D viewing, and a single, maximized viewport. Out of

the box, double-clicking the minus (–) sign switches to four equal-sized viewports showing different views of the geometry. Figure 22-1 illustrates what we’re talking about: In this example, you see four viewports, four different viewpoints, and four different visual styles. That’s a bit extreme for everyday work, but it gives you an idea of the possibilities.

Figure 22-1: 3D viewing from every which way.

We highly recommend working with multiple viewports when you’re modeling in 3D — that way you get to see exactly what you’re doing in all three dimensions, in real time. Our preference is to work mostly in the isometric viewport, so we make that one larger than the other three. The in-canvas

www.it-ebooks.info

Chapter 22: From Drawings to Models 495

viewport toggle will switch back and forth between the last multiple viewport you set up, and a maximized viewport. In the following steps, we explain how to set up the tiled-viewport configuration you see in Figure 22-3.

1.If you’re not already in the 3D Modeling workspace, click the Workspace drop-down list on the Quick Access Toolbar and choose 3D Modeling.

You can also click the Workspace Switching button on the status bar and again, select 3D Modeling. If the Materials Browser palette opens, close it.

2.Click New on the Quick Access Toolbar to open the Select Template dialog box.

If a new blank drawing appears and you don’t see the Select Template dialog box, someone has assigned a default template to this button in the Options dialog box. In that case, click the Application button (the Big Red A) and choose New, and then choose Drawing from the submenu.

3.Choose acad.dwt (choose acadiso.dwt if metric is your preference), and click Open.

Yes, we know there are ready-made 3D templates (acad3d.dwt and acadiso3d.dwt), but trust us — it’s easier to start this setup from a 2D template.

4.From the Viewports panel on the Ribbon’s View tab, choose Named.

The Viewports dialog box appears.

5.Click the New Viewports tab to make it current; then choose Four: Left (our preference) or Four: Right from the Standard Viewports list box.

The Preview panel shows a large, squarish viewport occupying most of the work area, with three small squarish viewports stacked on the left (or right). The default 2D setup shows the visual style of all four viewports as “2D Wireframe.” (We explain visual styles in Chapter 21.)

6.From the Setup drop-down list, choose 3D.

The visual styles remain as 2D Wireframe, but the view direction (listed as “Current” in 2D Setup) is now SE Isometric in the large viewport, while the three small viewports show Top, Front, and Right orthographic views.

When modeling in 3D, it’s nearly always helpful to look at your objects in different ways at the same time. When looking at orthographic views, same as with a drafted drawing, you probably want to see all your linework. But you can get a better sense of the three dimensionality of your model by looking at it in a shaded view. With multiple viewports, you can do both at the same time.

www.it-ebooks.info

496 Part V: On a 3D Spree

7.In the Preview area, click inside the large SE Isometric viewport and then choose Conceptual from the Visual Style drop-down list.

You’re almost finished in here. Rather than go through this setup every time you want to do some modeling, give your new viewport configuration a name.

8.In the New Name box at the top of the Viewports dialog box, enter a name — V3D, for example — for the configuration.

Figure 22-2 shows the new, named viewport configuration. After you close the Viewports dialog box, you can restore this configuration at any time by clicking the Named Viewports tab, choosing V3D, and clicking OK.

Figure 22-2: Setting up a 3D work environment in the Viewports dialog box.

9.Click OK to save the viewport configuration and close the Viewports dialog box.

In Figure 22-3, we turned off the grid in the three small ortho viewports, but whether you leave it on or turn it off is a matter of personal preference.

The ViewCube’s Home button can trip you up by changing to a view you don’t expect. (We introduce the ViewCube in Chapter 21.) If you want to keep the current SE Isometric viewpoint, be sure to reset the Home view. To do this, simply right-click anywhere in the ViewCube and choose Set Current View as Home from the menu that appears. And because you’ve gone to the trouble of setting up a shaded 3D viewport, why not make it a little more realistic and turn on perspective mode at the same time?

www.it-ebooks.info

Chapter 22: From Drawings to Models 497

Figure 22-3: 2D and 3D all at the same time.

10.In the large 3D viewport, right-click the ViewCube to display its shortcut menu and then choose Perspective With Ortho Faces (see Figure 22-4).

Selecting Perspective shows your orthographic views in perspective mode, and usually you don’t want that. Selecting Perspective with Ortho Faces resets the projection mode from perspective to parallel when you switch to an orthographic view.

Figure 22-4: Changing settings in the ViewCube’s right-click menu.

11.Repeat Step 10, this time selecting Set Current View as Home.

Now you can readily return to this viewport configuration, keeping the same viewpoint in all viewports, perspective projection in the 3D viewport, and parallel projection in the orthographic viewports.

www.it-ebooks.info