* Ctrl+N – Create a new file.
* Ctrl+O – Open an existing file.
* Ctrl+S – Save the current file.
* Alt+B – Export again.
* F9 – Run/Compile Map.
* Ctrl+Shift+S – Open Sound Browser.
Undo/Redo
* Ctrl+Z – Undo.
* Ctrl+Y – Redo.
Clipboard/Selection
* Ctrl+C – Copy objects to clipboard (also Ctrl+Insert).
* Ctrl+V – Paste objects from clipboard (also Shift+Insert).
* Ctrl+X – Cut objects to clipboard (also Shift+del).
* Shift+Q or Esc – Clear current selections.
* PgUp – Previous selection in "hit" list.
* PgDn – Next selection in "hit" list .
* Alt+Enter – Open up Object Properties for the currently selected objects.
Grid
* [ – Decrease the size of the grid.
* ] – Increase the size of the grid.
* Shift+R – Toggle grid on/off.
* Shift+W – Toggle snap to grid.
* P – Toggle 3D grid on and off (with mouse cursor in 3D view).
Grouping
* Ctrl+G – Group selected objects.
* Ctrl+U – Ungroup selected groups.
* Ctrl+R – Create prefab with selected objects.
* Ctrl+T – Tie to entity. Creates an entity with selected objects, or adds objects to an existing entity if one is also selected.
* Ctrl+W – Toggle Ignore Groups mode to bypass entity and group selection.
* Ctrl+Shift+W – Move selected solid entities to world.
* Ctrl+A – Auto-size 4 views to center.
* Shift+Z – Maximize/restore current viewport.
* Arrow keys – Nudge the current selection in the current 2D or 3D viewport.
* Shift+Arrow keys – Clone the current selection and nudge it the current 2D or 3D viewport.
* F6 – Cycles to the next active viewport.
* F6 – Cycles to the previous active viewport.
2D Views
* Ctrl+I – Flip selected objects vertically.
* Ctrl+L – Flip selected objects horizontally.
* Ctrl+B – Snap selected objects to grid (based on bounding box).
* Ctrl+Shift+B – Snap selected objects to grid (individually).
* Tab – Switch view types (top/side/front).
* +/- – Zoom in/out (hold Ctrl to synchronize all 2D views).
* Mouse Wheel – Zoom in/out (hold Ctrl to synchronize all 2D views).
* 1 to 9 – Preset zoom levels.
* Space – Hold space and left mouse button to drag view position.
* Alt – Disable snap to grid while dragging with the mouse.
* Ctrl+E – Center 2D Views on currently selected objects.
* Mouse Wheel – Zoom in/out (hold Ctrl to synchronize all 2D views).
3D View
* Space - While holding the spacebar:
o Holding the left mouse button allows you to rotate your angle of view in any direction, while the viewing point remains stationary.
o Holding the right mouse button will allow you to move left, right, up, and down while keeping the viewing angle constant.
* Space+Shift - While holding the spacebar and Shift:
o The left mouse button acts the same as above.
o The right mouse button allows you to move forward and backward, as well as from side to side.
* Mouse Wheel – Zoom in/out.
* W – Move camera forward.
* S – Move camera backward.
* A – Move camera (strafe) left.
* D – Move camera (strafe) right.
* z – Toggles 3D view "noclip" navigation mode.
* P – Toggle 3D grid on and off (with mouse cursor in 3D view).
* O – Display frames per second and yaw/pitch of camera (with mouse cursor in 3D view).
* 1 – Decrease far clipping plane.
* 2 – Increase far clipping plane.
* Ctrl+Shift+E – Center 3D View on selection.
Selection Tool
* Ctrl – Hold Ctrl and click to select multiple objects.
* Shift – Hold Shift when rotating to constrain rotation to 15 degrees; hold Shift when moving an object to create a copy (clone) of that object.
* Left mouse – Click and drag left mouse button to select with a box; press Enter to select objects hitting the box, or press Shift+Enter to select objects only entirely within the box.
* Esc – Cancel current selection
Camera Tool
* Shift or Alt – Hold Shift or Alt and click and drag left mouse button to create a new camera.
* PgUp – Cycle to the previous camera position.
* PgDn – Cycle to the next camera position.
* Delete – Delete the current camera position.
* Ctrl – Hold Ctrl and drag a camera or its point of interest to move both together.
Block Tool
* Left Mouse – Click and drag left mouse to draw a new brush shape.
* Enter – Create object drawn with block/entity tool.
* Esc – Delete object drawn with block/entity tool without creating it.
* Alt+Shift+C – Insert original prefab.
Texture Application Tool
* Ctrl – Hold Ctrl and click to select multiple faces.
* Shift – Hold Shift and click a face to select all faces on the brush.
* Shift+Ctrl – Hold Shift and Ctrl, click a face to add all faces on the brush to the current selection.
* Right-click – Apply the current material settings to the face that is clicked.
* Alt+Right-click – Apply the current material settings to the face that is clicked, with wrapping.
Displacement Editing Tool, Select Mode
* Ctrl – Hold Ctrl and click to select multiple faces.
* Shift – Hold Shift and click a face to select all faces on the brush.
* Shift+Ctrl – Hold Shift and Ctrl, click a face to add all faces on the brush to the current selection.
Displacement Editing Tool, Paint Geometry Mode
* Ctrl – Hold Ctrl and click to select multiple faces.
* Alt – hold Alt and drag to alter the size of the spatial editing brush.
* Shift – hold Shift and drag a vertex to nudge the vertex along the editing axis.
* Alt+Right-click – Click any brush or displacement face to make that face’s normal the current painting axis.
Displacement Editing Tool, Paint Alpha mode
* Ctrl – Hold Ctrl and click to select multiple faces.
* Shift+Ctrl – Hold Shift and Ctrl, click a face to add all faces on the brush to the current selection.
Overlay Tool
* Shift – Hold Shift and drag a overlay vertex to snap it to another vertex.
* Ctrl – hold Ctrl and click to select multiple overlays.
Clipper Tool
* Left mouse– Click and drag left mouse to create a new clip plane.
* Shift – Hold Shift and drag with the left mouse button to create a new clip plane without performing the previous clip.
* Enter – Perform clip
* Ctrl – hold Ctrl and drag with the left mouse button to move both handles of the clipping plane.
* O – Toggle clip distance display on and off (with mouse cursor in 2D view).
* Shift+X – Cycle through clip modes.
Vertex Edit Tool
* Ctrl+F – Split faces (vertex manipulation) – must have two edges or vertices selected.
* Alt+E – Open Vertex Scaling dialog.
* Enter – Close Vertex Scaling dialog and perform scale.
* Shift+V – Cycle vertex/edge display modes.
Miscellaneous
* Shift+L – Toggle Texture lock.
* Ctrl+M – Open Transform dialog.
* Alt+P – Open Check for Problems dialog.
* Esc – Abort current tool/mouse operation (drag/drop) or clear current selection.
* Ctrl+Shift+G – Go to Brush Number dialog.
* Ctrl+Shift+F – Open Find Entities dialog.
* Ctrl+Shift+R – Open Replace Entities dialog.