#!F-adobe-helvetica-medium-r-normal--18*
#!N 
#!CDarkGreen #!N  #!Rroam 
Changing the Look-to Point #!N #!EC #!N #!N Data Explorer maintains 
the look-to point at the center of the Image window. You 
can use the  #!F-adobe-times-bold-r-normal--18*   Roam #!EF mode to change the look-to 
point. #!N #!N To change the look-to point: #!N #!I0 #!N 
 #!F-adobe-times-medium-r-normal--18*   #!N #!N #!I30 #!N 1. Select the  #!F-adobe-times-bold-r-normal--18*   Roam #!EF 
mode by using the  #!F-adobe-times-bold-r-normal--18*   Mode #!EF option box or the 
 #!F-adobe-times-bold-r-normal--18*   Ctrl+W #!EF accelerator key. #!N #!I30 #!N 2. A wire-frame 
box appears around the image. The current look-to point is marked 
by a small square box. To move the look-to point, select 
the point by pressing the  #!F-adobe-times-medium-i-normal--18*   left #!EF mouse button and 
holding the mouse pointer on it. You can then move the 
cursor by dragging the selected point inside the box. When the 
left mouse button is depressed on the point, the mouse cursor 
disappears (the look-to point remains) and the three projections (one for 
each axis) appear inside the wire-framed box as dots, similar to 
the 3-D cursor function illustrated in  #!Ltdcurs59,dxall321 f Figure 59  #!EL  . When you release 
the mouse button, the location of the point becomes the new 
look-to point, and the image view is updated. #!N #!N Alternatively, 
double-clicking on a point in the Image window changes the look-to 
point to the position on which you double-click. You can set 
the look-to point to a location outside the current boundary box 
of the object using this method. Note: You can also enable 
 #!F-adobe-times-bold-r-normal--18*   Roam #!EF mode by using the  #!F-adobe-times-bold-r-normal--18*   intrctnMode #!EF parameter 
to the Image tool (see Image in IBM Visualization Data Explorer 
User's Reference). #!N #!I0 #!N #!EF #!N #!N #!N The directions 
of the axes are indicated by a wire-frame 3-D axes diagram 
in the lower right-hand corner of the Image window. To move 
the look-to point, the movement of the mouse must be along 
the same direction as one of the axes. If you move 
the mouse in a direction that does not correspond to any 
of the axes directions, the point does not move. Because of 
this, the movement of the look-to point is constrained to six 
directions (i.e., the positive and negative directions for each of the 
three axes). #!N #!N Note that since perspective projection does not 
preserve parallel lines, the directions in the axes diagram do not 
necessarily correspond to the direction that the point moves in the 
Image window. However, these axes do correspond with the values of 
the coordinates. #!N #!N While using orthographic projection, the movement of 
the point in the Image window corresponds with the directions of 
the axes diagram. #!N #!N The  #!F-adobe-times-bold-r-normal--18*   Constraints #!EF option appears 
in the  #!F-adobe-times-bold-r-normal--18*   View Control... #!EF dialog box when you select 
 #!F-adobe-times-bold-r-normal--18*   Roam #!EF mode. #!N #!N You can further restrict the 
movement of the look-to point by using the  #!F-adobe-times-bold-r-normal--18*   Constraints #!EF 
option. This allows you to constrain movement of the point to 
two directions (i.e., the positive and negative directions of a particular 
axis). Select an axis to restrict movement to by clicking on 
the  #!F-adobe-times-bold-r-normal--18*   Constraints #!EF option box and selecting the desired axis 
(X, Y, or Z). Once this is done, you are able 
to move the look-to point along only the selected axis, while 
the values of the other two axes remain constant. #!N #!N 
You may want to position the cursor in two steps, using 
different views for each step. For example, you can position the 
 #!F-adobe-times-medium-i-normal--18*   x #!EF and  #!F-adobe-times-medium-i-normal--18*   y #!EF coordinates using the front 
view, and the  #!F-adobe-times-medium-i-normal--18*   z #!EF coordinate using the side view. 
#!N #!N To release the constraints on an axis, choose the 
 #!F-adobe-times-bold-r-normal--18*   None #!EF option. #!N #!N While in  #!F-adobe-times-bold-r-normal--18*   Roam #!EF 
mode, the center and right mouse buttons have the same functions 
as they do in  #!F-adobe-times-bold-r-normal--18*   Rotate #!EF mode. #!N #!N #!N 
 #!F-adobe-times-medium-i-normal--18*   Next Topic #!EF #!N #!N  #!Lpanzoom,dxall308 h Panning and Zooming into and out of the Image  #!EL  #!N  #!F-adobe-times-medium-i-normal--18*   #!N 
