Toggle SubSurf On/Off

`Shift` + `O`

All hotkeys for Blender 3D (Windows)

Window Go to Previous Screen	`Ctrl` + `Left Arrow`
Window Go to Next Screen	`Ctrl` + `Right Arrow`
Window Maximize Window	`Ctrl` + `Up Arrow`
Window Retrun to Previous Window Size	`Ctrl` + `Down Arrow`
Window Data View	`Shift` + `F4`
Window 3D Window	`Shift` + `F5`
Window IPO Window	`Shift` + `F6`
Window Buttons Window	`Shift` + `F7`
Window Sequence Window	`Shift` + `F8`
Window Outliner Window	`Shift` + `F9`
Window Image Window	`Shift` + `F10`
Window Text Window	`Shift` + `F11`
Window Action Window	`Shift` + `F12`
Universal Lasso select	`Ctrl` + `Click`
Universal Cancel Blender Functions	`Esc`
Universal Open Toolbox	`Spacebar`
Universal Start/Quit Editmode	`Tab`
Universal Append parts of other files	`Shift` + `F1`
Universal Export Scene as a DXF file	`Shift` + `F2`
Universal Load Blender File	`F1`
Universal Write Blender File	`F2`
Universal Writes A Picture	`F3`
Universal Display Logic Context	`F4`
Universal Display Shading Context	`F5`
Universal Display Shading Context and Texture Sub-Context	`F6`
Universal Display Object Context	`F7`
Universal Display Shading Context and World Sub-Context	`F8`
Universal Display Editing Context	`F9`
Universal Display Scene Context	`F10`
Universal Hide/Show Render Window	`F11`
Universal Start Rendering from Active Camera	`F12`
Universal Save A Scrrendump of Active Window	`Ctrl` + `F3`
Universal Save A Screendump of Whole Blender Screen	`Ctrl` + `Shift` + `F3`
Universal Go to Previous Frame	`Left Arrow`
Universal Go to Next Frame	`Right Arrow`
Universal Go forward 10 Frame	`Up Arrow`
Universal Go Backward 10 Frame	`Down Arrow`
Universal Go to First Frame	`Shift` + `Left Arrow`
Universal Go to Last Frame	`Shift` + `Right Arrow`
Universal Change Current Blender Window to Animation Playback Mode	`Alt` + `A`
Universal Current Window and 3D Window go to Animation Playback Mode	`Alt` + `Shift` + `A`
Universal Insert Key Menu	`I`
Universal Toggle the Render Buffers	`J`
Universal Open the Last Saved File	`Ctrl` + `O`
Universal Quit Blender	`Q`
Universal Timer Menu	`Alt` + `Ctrl` + `T`
Universal Save User Defaults	`Ctrl` + `U`
Universal Write File	`Ctrl` + `W`
Universal Write Videoscape File	`Alt` + `W`
Universal Erase All	`Ctrl` + `X`
Universal Undo	`Ctrl` + `Z`
Universal Redo	`Ctrl` + `Y`
Object Mode All Objects are Displayed in Center	`Home`
Object Mode Select Next Object Key	`PgUp`
Object Mode Select Previous Object Key	`PgDn`
Object Mode Add to Selection the Next Object Key	`Shift` + `PgUp`
Object Mode Add to Selection the Previous Object Key	`Shift` + `PgDn`
Object Mode Start/Stop EditMode	`Tab`
Object Mode Select All	`A`
Object Mode Apply Size and Rotation	`Ctrl` + `A`
Object Mode Add Menu	`Shift` + `A`
Object Mode Select Border	`B`
Object Mode Render Border	`Shift` + `B`
Object Mode Centre View	`C`
Object Mode Convert Menu	`Alt` + `C`
Object Mode Copy Menu	`Ctrl` + `C`
Object Mode Centre Zero View	`Shift` + `C`
Object Mode Draw Mode Menu	`D`
Object Mode Add Duplicate	`Shift` + `D`
Object Mode Add Linked Duplicate	`Alt` + `D`
Object Mode Draw Image as Wire	`Ctrl` + `D`
Object Mode Start/Stop EditMode	`Alt` + `E`
Object Mode Toggle Face Select Mode On/Off	`F`
Object Mode Sort Faces	`Ctrl` + `F`
Object Mode Grab Mode	`G`
Object Mode Clears Translation	`Alt` + `G`
Object Mode Group Selection	`Shift` + `G`
Object Mode Insert Object key	`I`
Object Mode Join Object	`Ctrl` + `J`
Object Mode Show Keys	`K`
Object Mode Enable Transformation of Entire Animation System	`Shift` + `K`
Object Mode Make Selected Object Local	`L`
Object Mode Link Selected	`Ctrl` + `L`
Object Mode Select Linked	`Shift` + `L`
Object Mode Mirror Menu	`Ctrl` + `M`
Object Mode Number Panel	`N`
Object Mode Clear Origin	`Alt` + `O`
Object Mode Toggle SubSurf On/Off	`Shift` + `O`
Object Mode Make Selected Object the Child of Active Object	`Ctrl` + `P`
Object Mode Rotate Mode	`R`
Object Mode Clear Rotation	`Alt` + `R`
Object Mode Size Mode	`S`
Object Mode Clear Size	`Alt` + `S`
Object Mode Snap menu	`Shift` + `S`
Object Mode Texture Space Mode	`T`
Object Mode Make Selected Object Track Active Object	`Ctrl` + `T`
Object Mode Clear Old Style Track	`Alt` + `T`
Object Mode Make Object Singl User	`U`
Object Mode A PopUp with User Choices	`Ctrl` + `L`
Object Mode Switches in/out of Vertex Mode	`V`
Object Mode Object Image Aspect	`Alt` + `V`
Object Mode Open Object Booleans Menu	`W`
Object Mode Delete Selected Object	`X`
Object Mode Toggle Solid Mode On/Off	`Z`
Object Mode Toggle Shaded Mode On/Off	`Shift` + `Z`
Object Mode Toggle Textured Mode On/Off	`Alt` + `Z`
General Editing Start/Stop Edit Mode	`Tab`
General Editing Switches between Vertex Select,Edge Select and Face Select Modes	`Ctrl` + `Tab`
General Editing Select/Unselect all	`A`
General Editing Select Circle	`B`
General Editing Bring up Options Menu for It	`Ctrl` + `H`
General Editing Number Panel	`N`
General Editing Switch in/out of Proportional Editing	`O`
General Editing Toggle between Smooth and Sharp Proportional Editing	`Shift` + `O`
General Editing Separate	`P`
General Editing Make Vertex Parent	`Ctrl` + `P`
General Editing Shear	`Ctrl` + `S`
General Editing Undo	`U`
General Editing Special Popup Menu	`W`
General Editing Warp	`Shift` + `W`
Mesh Editing Edge Select	`Ctrl` + `Alt` + `Right Click`
Mesh Editing Toggle Curve Cyclic Mode On/Off	`C`
Mesh Editing Extrude selected	`E`
Mesh Editing Make Edge/Face	`F`
Mesh Editing Fill Selected	`Shift` + `F`
Mesh Editing Beauty Fill	`Alt` + `F`
Mesh Editing Flip Faces	`Ctrl` + `F`
Mesh Editing Knife Tool Menu	`K`
Mesh Editing Select Linked	`L`
Mesh Editing Mirror	`M`
Mesh Editing Undo	`U`
Mesh Editing Redo	`Shift` + `U`
Mesh Editing Special Menu	`W`
Mesh Editing Erase Selected	`X`
Mesh Editing Split	`Y`
Curve Editing Set Cyclic Curve On/Off	`C`
Curve Editing Extrude Curve	`E`
Curve Editing Add segment	`F`
Curve Editing Toggle Handle Align/Free	`H`
Curve Editing Select Linked	`L`
Curve Editing Mirror	`M`
Curve Editing Tilte Mode	`T`
Curve Editing Vector Handle	`V`
Curve Editing Erase Selected	`X`
Metaball Editing Mirror	`M`
Metaball Editing Select Row	`Shift` + `R`
VertexPaint All vertex colors are erased	`Shift` + `K`
VertexPaint Undo	`U`
VertexPaint Shared Vertexcol	`W`
Font Move Text Cursor 1 Position Forward	`Right Arrow`
Font Move Text Cursor to End of Line	`Shift` + `Right Arrow`
Font Move Text Cursor 1 Position Backward	`Left Arrow`
Font Move Text Cursor to start of lIne	`Shift` + `Left Arrow`
Font Move text cursor 1 line forward	`Down Arrow`
Font Move Text Cursor to End of Line	`Shift` + `Down Arrow`
Font Move Cursor to 1 Line Back	`Up Arrow`
Font Reload Original Data	`Alt` + `U`
Font Paste Text	`Alt` + `V`
UV Editor LSCM Unwrapping	`E`
UV Editor Pin Selected Vertices	`P`
UV Editor UnPin selected Vertices	`Alt` + `P`
Edge Select Select Edge Loop	`Alt` + `Click`
Face Select Select Face Loop	`Alt` + `Click`
Face Select Switches to EditMode	`Tab`
Face Select Select Linked Uvs	`L`
Face Select Rotate UV Coordinates	`R`
Face Select Calls UV Calculation	`U`