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     This task explains how to use 
     the preselection navigator (or the keyboard arrows) for selecting hidden or 
     coincident elements, or elements located elsewhere in the specification 
     tree. | 
   
   
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     Note: the preselection 
     navigator cannot be used with selection filters. | 
   
   
     
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     Open the document
     Select.CATProduct. | 
   
   
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     Displaying the Preselection Navigator
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     Method 1
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Click anywhere in the geometry area.  
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Position your pointer over the object you want to select.  
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Press any keyboard arrow (up, down, right or left) or
       Ctrl + F11. 
       
         
           
             
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             You can also 
             press Alt + the left mouse button (except when working 
             on Sun Solaris operating systems). | 
            
           
             | The preselection navigator appears.
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     Method 2
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Select Tools > Options > General >
       Display then the
       Navigation tab.  
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       Select the Display the preselection navigator after ... seconds 
       check box, set the spinner to the time delay.  
       
         
           
             | The spinner sets the amount of time, in seconds, 
             which elapses before the preselection navigator appears after 
             pointing at an object. | 
            
          
        
        
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Make sure that the following three check boxes are 
       selected as well: 
       
         
           
             
             
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Display immersive list for preselection 
               navigator  
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Prehighlight faces for preselection 
               navigator  
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Display immersive viewer for preselection 
               navigator.  
              
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Click OK to close the Options 
       dialog box.  
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Point to the part of the object you want to select. 
       
         
           
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              The selection tool is 
             displayed after the time delay you set in step 2:  | 
            
           
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     About display options
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     As explained above, a certain 
     number of options are available for customizing the display of your 
     preselection navigator. Below are examples of what you see in the geometry 
     area when these options are activated or deactivated:
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       - Prehighlight faces 
       for preselection navigator
 
       You can activate/deactivate the highlight of preselected faces by 
       selecting/clearing the Prehighlight faces for preselection navigator 
       check box under the Navigation tab.  
       By default, this option is deactivated and in that case, the preselected 
       face looks like this: 
      
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       When the Prehighlight faces for preselection navigator 
       check box is selected, the preselected face looks like this: 
      
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       - Display immersive list for 
       preselection navigator
 
       You can activate/deactivate the immersive list's display by 
       selecting/clearing the Display immersive list for preselection 
       navigator check box. The immersive list displays all the stacked 
       elements you can preselect. 
       By default, this check box is activated which means that the immersive 
       list is displayed as shown below: 
      
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       - Display 
       immersive viewer for preselection navigator
 
       You can activate/deactivate the immersive viewer's display by 
       selecting/clearing the Display immersive viewer for preselection 
       navigator check box. The immersive viewer provides a visual 
       feedback on the preselected element and lets you validate your selection. 
       By default, this check box is selected which means that the immersive 
       viewer is displayed as shown below: 
      
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       When the Display immersive viewer for preselection navigator 
       check box is cleared, the result is as follows: 
      
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       - Display 
       auxiliary viewer for preselection navigator
 
       You can activate/deactivate the auxiliary viewer's display by 
       selecting/clearing the Display auxiliary viewer for preselection 
       navigator check box. The auxiliary viewer lets you perform viewing 
       operations with the mouse such as zoom, rotate or pan. 
       By default, this check box is cleared. When the option is activated, you 
       see something like this in the geometry area: 
      
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       The use of this check box is detailed further in this scenario. 
      
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       - Color
 
       The default color used to highlight selected and preselected elements is 
       "orange" but you can choose other colors using the Selected elements 
       and Preselected elements lists available in the 
       Visualization tab. 
       For instance, if you select a "pink" color in the Selected elements 
       list, the result looks something like this: 
      
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     Using the Preselection Navigator
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     The 
     following diagram describes graphic selection tool features:  | 
   
   
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     The preselection navigator is 
     made up of the following elements:
     
       - a circle providing a visual feedback for the pointed object. This 
       circle with an opaque background shows the preselected element and 
       displays the surrounding elements in transparency. The circle keeps the 
       proportions of the current viewer
 
       - arrow controls to navigate:
         - "in-depth" using up/down arrows
 
         - up and down in the object hierarchy using left and right arrows
 
        
        
       - a cross pinpoints the preselected location. Four arrows are used for 
       navigating or scrolling through the object you point at. These arrows 
       turn black when you reach an extremity
 
       - a list of all the stacked elements you can preselect. This list 
       indicates the selection path and the identity of each element. This 
       information is identical to the one displayed in the status bar. 
 
       You can choose to display or not the immersive list of elements you can 
       preselect (shown in the example below). To do so, select or clear the
       Display immersive list for preselection navigator check box in 
       the Navigation 
       tab 
       - an auxiliary viewer displaying the preselected object. This viewer 
       also lets you perform viewing operations with the mouse such as zoom, 
       rotate or pan. By default, this viewer is not displayed and has to be 
       activated via the Navigation tab as explained further in this 
       task. 
 
      
     An invisible area around the selection tool determines the tool's 
     sensitivity. 
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Once the preselection navigator is displayed, click the 
       up arrow to navigate "in-depth", in other words, from the front to the 
       back of the object, to highlight hidden, superposed or coincident 
       elements. 
       
         
           
             | This method is particularly 
             useful for large parts since it lets you select, for example, 
             edges, faces, etc. which are not visible or accessible near the 
             front of the part.  | 
            
           
             | The cursor shape changes 
             according to the type of the preselected element as shown below:
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             | point... | 
             edge...  | 
            
           
             
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             | or face:  | 
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             | The identity of the 
             preselected element is displayed in the status bar: | 
            
           
             
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             | Note: the 
             preselection navigator lets you use the contextual menu.  | 
            
           
             | You can also navigate 
             between different objects, not just inside single objects. When one 
             object hides another, the preselection navigator also lets you 
             select elements belonging to the hidden object.  | 
            
          
        
        
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Click the down arrow to navigate in the opposite 
       direction, towards the front of the object. 
       
         
           
             
             There are two other ways to 
             navigate using the mouse:
               - position your cursor over the circle, then click with the 
               middle mouse button to navigate inside the object. As you click, 
               the corresponding element path is highlighted in the list 
               displayed to the right
 
               - move the mouse over the list of element paths. As you do 
               this, the element corresponding to each path you point at is 
               pre-highlighted in the circle. Then, click the desired path to 
               select the corresponding element.
 
              
             Moreover, when pointing at an element in the circle or at a path 
             in the list, you can right-click to display the contextual menu as 
             shown in the following two examples:  | 
            
           
             | Example 1 - when 
             pointing at an element in the circle | 
            
           
             
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             | Example 2 - when 
             pointing at a path in the list | 
            
           
             
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             To 
             select a contextual command, right-click it.
              You can also press the up and down arrows to achieve the same 
             effect, and validate your selection by pressing Enter. 
             Using any of these keys displays the selection tool automatically.  | 
            
           
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             The navigation is cyclic: when you reach the end of the selection 
             path using the up and down keys, the preselection navigator 
             automatically goes back to the starting point (i.e. the highest 
             element in the hierarchy) and you can then re-start navigating.
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Click the left and right arrows to navigate up and down 
       in the object's hierarchy.  
       
         
           
             | For example, click the left 
             arrow and look at the specification tree to see that each click on 
             the left arrow takes you to the top of the tree, then click the 
             right arrow to navigate downwards.  | 
            
           
             
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             Similarly, you can 
             also press the left and right keys to achieve the same effect, and 
             validate your selection by pressing Enter or using the 
             left mouse button.  | 
            
           
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             When preselecting an edge, a 
             prehighlight is also provided which is especially useful in case of 
             overlapped elements:  | 
            
           
             
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Select Tools > Options > General > Display 
       then access the Navigation tab and select the Display 
       auxiliary viewer for preselection navigator check box.  
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Click anywhere in the geometry area, then position your 
       pointer over the object and restart navigating by clicking the up or left 
       arrow.  
       An additional window opens and displays the object with the element you 
       have preselected: 
       
         
           
             
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             | The Auxiliary Viewer 
             window lets you manipulate the object and perform
             viewing operations with 
             the mouse such as rotate, zoom or pan as shown below: | 
            
           
             
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             | Rotate | 
             Zoom  | 
            
           
             | To hide the viewer, simply 
             re-access the Navigation tab then clear the Display 
             auxiliary viewer check box. | 
            
          
        
          
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To validate your selection and exit the preselection 
       navigator, use one of the following methods below, depending on the 
       display options that have been activated: 
       
         
           
             
             
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click the circle in the center of the immersive 
               viewer  
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or, click the desired item in the immersive list  
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or, click the element directly on the object.  
              
             The item is selected:  | 
            
           
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       The selection tool disappears, in any case, once a selection has been 
       made, or if you point or click outside the selection activation area 
       around the selection tool. 
      
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