When modifying synchronous models or assemblies it is often necessary to add elements to or remove elements from a set of selected elements based on the topological or attribute data of a currently selected element. For example, you may want to move all the holes in a specific area of a model that also match the size of a currently selected hole. On the Home tab→Select group, from the Select command list, you can use the Select modes and Selection Manager to add elements to or remove elements from a select set based on a currently selected element.
You select faces and features on the model directly with the assistance of QuickPick. You also select features from PathFinder.
Use the Select Filter options on the Home tab in the Selection Filters group to add or remove elements from a select set.
When building a select set with the Selection Manager, the select criteria are defined with respect to a currently selected element. This element is called the focus element. Any element which is currently selected can be used as a focus element.
Press Shift+Spacebar to start Selection Manager mode or click the Selection manager mode on the Select command list. The Selection manager icon 
appears on the cursor.
To display the Selection Manager menu, click when the selection manager icon appears.
The displayed menu options are specific to the focus element--the element which the cursor is over. For example, you would not see the Equal Diameter option when the focus element is a planar face. You cannot add hidden elements to a select set.
When you position the cursor over a menu option, the elements that match the option criteria are highlighted in the graphics window. You also can drag the menu to a new location to better visualize the model.
You can also use the menu more than one time to build the select set you want.
Some menu options on the Selection Manager shortcut menu support defining a 3D box when the Use Box selection option is set. This allows you to limit the selection volume to a size you define. For example, you can use the Equal Diameter option with a 3D box to select only the cylindrical faces that fall within a 3D box you define with the cursor in the graphics window.
The default selection mode in called Normal Select mode. Each time you select a face, the previously selected face is deselected. Press Spacebar to cycle through the selection modes.
The add/remove selection mode is used to build a select set. In the normal mode, select a face and then press the Spacebar to switch to the Add/Remove mode. Each face selected in this mode is added to the select set. If a face is selected that has already been selected, it is deselected. The graphic handle remains on the first face selected. Both selected and deselected faces highlight as the cursor moves over them.
The Add mode only adds faces to the select set. Only deselected faces highlight as the cursor moves over faces. To set the mode to Add, cycle through the select modes by pressing Spacebar.
The Remove mode only removes (deselects) faces from the select set. Only selected faces highlight as the cursor moves over faces. To set the mode to Remove, cycle through the select modes by pressing Spacebar.
To clear the select set, press Esc, double-click, or choose Clear Selection command in the Home tab→Select group.
When defining a select set by selecting features in PathFinder, Shift select adds to the select set in Add and Add/Remove selection modes. Shift select does not invert the selection or remove items from the set. Shift select in the Remove selection mode performs no action. Ctrl select in the Remove selection mode does not add items to the select set. It removes items if they are already selected.