Copyright Goodheart-Willcox Co., Inc. Chapter 3 Viewing and Displaying Three-Dimensional Models 69 are discussed here. The Rewind tool is addressed in the View Object Wheel section, discussed earlier. Forward The principal tool in the Tour Building wheel is the Forward tool. It is similar to the Walk tool in the Full Navigation wheel. However, it only allows forward movement from the current viewpoint. This tool requires a center point to be set on the model from within the tool. The existing center point cannot be used. First, move the cursor and steering wheel to the point on the model that will be the target (center point). Next, pick and hold the Forward tool. The pick point becomes the center point and a drag distance indicator is displayed. See Figure 3-22. This indi- cator shows the starting viewpoint, the center point, and the surface of the model that you selected. Hold the mouse button down while moving the pointer up. The orange location slider moves to show the current viewpoint relative to the center point. As you move closer to the model, the green center point icon increases in size, which also provides a visual cue to the zoom level. Look The Look tool is used to rotate the view about the center of the view. When the tool is activated, the cursor appears as a half circle with arrows. See Figure 3-23. As you move the cursor down, the model moves up in the view as if you are actually tilting your head down. Similarly, as you “look” away from the model to the right or left, the model appears to move away from your line of sight. If the vertical movement does not seem intuitive to you, it is easy to change. Open the Steering Wheels Settings dialog box and check the Invert vertical axis for Look tool check box. Now, when using the Look tool, moving the cursor up or down also moves the object in the same direction. The distance between you and the model remains the same and the orientation of the model does not change. Therefore, you would not want to use this tool if you wanted to see another side of the model. Up/Down As the name indicates, the Up/Down tool moves the view up or down along the Y axis of the screen, regardless of the orientation of the current UCS. Pick and hold on the tool and the vertical distance indicator appears. See Figure 3-24. Two marks on this indicator show the upper and lower limits within which the view can be moved. The Slider Figure 3-22. The drag distance indicator is displayed when using the Forward tool. This indicator shows the start point of the view and the selected surface of the model. The slider indicates the current view position relative to the starting point. Figure 3-23. The Look tool cursor appears as a half circle with arrows.