Selection hotkeys
 
 
 
Select All Ctrl + A Selects all models in the 3D View.
Invert Selection Ctrl + Shift + I Selects any un-selected faces and deselects any existing selected faces in the 3D View.
Deselect All Ctrl + D Clears the current selection.
Grow Selection Ctrl + ] Selects faces adjacent to the currently selected faces. Requires at least one face to be pre-selected.
Select Level Shift + A Selects all visible faces belonging to the subdivision level of the active face (the face under the cursor when the hotkey is pressed).
Select Face Shift + S Selects the active face (the face under the center of the cursor when the hotkey is pressed).
Drag Rectangle Middle button + Left button Choose a selection tool from the Select/Move Tools tray then press the left and middle button simultaneously while dragging around the item. To make this mode the default for a selection tool, choose Rectangle under the Selection Mode tool property.