Changing Your Point of View

Eventually, you'll want to be able to examine your model from different angles. If you are working on a building design, you might even want to see what it's like from inside your design. The AutoCAD Dashboard provides all the tools you'll need to get the view you want.

If you look at the 3D Navigate control panel, you'll see a set of tools for getting around in your model. (See Figure 6.4 earlier in this chapter.) To the left, you'll see the usual Pan and Zoom tools, and they work the same way in 3D as they do in 2D. But if you look at the tools to the right, things get a little less familiar. The following sections will show you what these other tools do.

If you still have the file open from the previous exercise, you can try these 3D navigation tools on the current model. Otherwise, you can open a new file using the acad3D.dwt template and create a box or other object to use as a practice visual target.

Moving Around Your Model

One of the first tasks you'll want to do with a model is look at it from all angles. The Constrained Orbit tool is perfect for this. To use it, click the tool, and then drag in the drawing area. As you drag, the view will revolve around your model. You'll also notice that the cursor changes to an orbit icon to let you know you are using the Constrained Orbit tool.

If you have several objects in your model, you can select an object that you want to revolve around and then click the Constrained Orbit tool. It also helps to pan your view so that the object you select is in the center of the view.

When you have reached the view you want, right-click, and choose Exit. You are then ready to make more changes or use another tool.

Just as with the Zoom and Pan features, you can gain instant access to the Constrained Orbit feature by using the scroll wheel of your mouse. Hold down the Shift key, click, and then drag the scroll wheel. Your view will rotate just as it would with the Constrained Orbit tool.

Changing Where You Are Looking

AutoCAD uses a camera analogy for views in your 3D model. With a camera, you have a camera location and a target, and you can fine-tune both in AutoCAD. Using the Constrained Orbit tool is a bit like moving a camera around an object. Using the Swivel tool is like keeping the camera stationary while pointing in a different direction.

At first, the Swivel tool might seem just like the Pan tool. But in the 3D world, Pan actually moves both the camera and the target in unison. Using Pan is a bit like pointing a camera out the side of a moving car. If you don't keep the view in the camera fixed on an object, you are panning across the scenery. Using the Swivel tool is like standing on the side of the road and turning the camera to take in a panoramic view.

To use Swivel, click the Swivel tool, and then drag across the view. You'll notice that the icon changes to a camera with a swivel arrow. When you've adjusted your view to your liking, right-click, and choose Exit.

Flying through Your View

Another tool for getting around in your model is the Walk/Fly tool. If you are familiar with computer games, this tool is for you. When you click the Walk tool in the 3D Navigate control panel, you first see a message box telling you how to use Walk.

It tells you all you need to know about the Walk tool. Click the Close button, and you can use the arrow keys to move through your model. Drag to change the direction in which you are looking.

If you press the F key, Walk changes to Fly mode. The main difference between Walk and Fly is that in Walk, both your position in the model and the point in which you are looking move with the Up and Down arrow keys. Walk is a bit like Pan. When you are in Fly mode, the arrow keys move you toward the center of your view, which is indicated by crosshairs.

In addition to the crosshairs, you will see a palette that shows your position in the drawing from a top-down view.

You can use the palette to control your view by clicking and dragging the camera or the view target graphic. If you prefer, you can close the palette and continue to "walk" through your model. When you are finished using Walk, right-click, and choose Exit.

Saving a View

You will eventually arrive at a view that you want to save and return to later. You can use the New View option in the 3D Navigate control panel to save the current view under a name that you specify. You can save as many views as you want for study or presentation purposes.

To save a view, click the drop-down list in the 3D Navigate control panel, and then choose New View. (See the left image in Figure 6.20.) The New View dialog box appears, as shown in the right image of Figure 6.20.

Figure 6.20: The drop-down list in the 3D Navigate control panel and the New View dialog box

Enter a name for your view at the top of the dialog box, select Current Display from the Boundary settings, and then click OK.

You can then restore your saved view from the same drop-down list in the 3D Navigate control panel. Your saved view's name appears at the top of the list.

Creating a Camera

Another way to save views is by using cameras. Cameras provide some additional controls, such as focal length and view angle. You can place as many cameras as you like in your model and then quickly call up the view from each camera. Unlike views saved using the New View dialog box, you can always make changes to a camera's view once you've created it.

To create a camera, do the following:

1. Click the Create Camera tool in the 3D Navigate control panel.

   

2. At the Specify camera location: prompt, you'll see a camera attached to the cursor. Select a location for the camera. The camera appears in the drawing, as shown in Figure 6.21.

3. At the Specify target location: prompt, you'll see a rubber-banding line from the camera to the cursor indicating the direction of the view from the camera. Click a location for the target location.

   

4. At the Enter an option [?/Name/LOcation/Height/Target/LEns/Clipping/View/ eXit]<eXit>: prompt, choose Exit from the Dynamic Input menu, or enter x↲.

Figure 6.21: Placing a camera in your drawing

Once you've placed a camera, you can begin to adjust its location using grips. To do this, click the camera to display its grips. A Camera Preview dialog box also opens to show you roughly what the view from the camera looks like.

You can then click a grip and move it to change the location. Click again to fix the location of the grip. You can hover over the camera or camera target's grip before clicking it to display the Grip tool. This will aid you in adjusting the vertical or Z location for the camera.

1. Place the cursor on the camera or target grip, but don't click. After a moment, you will see the Grip tool (see Figure 6.22).

2. Move the cursor to the axis within which you want to move the grip. A line appears whose color corresponds to the axis on which your cursor is resting.

3. When you see that line, you can click to move the grip along that line (see Figure 6.22). As you move the grip, you can use the camera preview window to help guide your grip location.

4. When you're satisfied with your view, click again to fix the grip's location.

Figure 6.22: Using the Grip tool to constrain motion to the x-, y-, or z-axis

Once you've created a camera, you can open that camera's view in the AutoCAD window through the 3D Navigate drop-down list. AutoCAD gives new cameras a default name of Camera1, Camera2, and so on; so to see the view from the first camera you create, click the 3D Navigate drop-down list, and select Camera1.

Changing a Camera's Properties

Just as with any AutoCAD object, cameras have properties. When you click a camera, then right-click, and finally select Properties, the Properties palette for the camera appears. Two properties that you'll want to become familiar with are the camera name and lens length. You might want to change the camera name to something more meaningful to your project. The lens length lets you set the field of view in terms of a camera's focal length (see Figure 6.23).

Figure 6.23: The Properties palette for a camera

Changing from Perspective to Parallel Projection

When you create a new drawing using the acad3D.dwt template, you are automatically given a perspective view of the file. If you need a more schematic parallel projection style of view, select the Parallel Projection tool in the 3D Navigate control panel (see Figure 6.24).

Figure 6.24: The Parallel Projection and Perspective Projection tools

You can return to a perspective view by clicking the Perspective Projection tool next to the Parallel Projection tool, as shown in Figure 6.24.