Mel & Hot Keys Review

What’s MEL?  Maya Embedded Language  Most of Maya's interface is built using MEL commands and scripts.

Why Use MEL?  Bypass Maya's user interface, quickly create shortcuts, and access advanced features.  Enter exact values for attributes, bypassing any restrictions to precision imposed by the interface.  Customize the interface for specific scenes, changing default settings to settings you prefer for a particular project.  Create MEL procedures and scripts that carry out custom modeling, animation, dynamics, and rendering tasks.

MEL in the Expression Editor  translateY = ball.translateZ; Or  ty = ball.tz;  ball.tx = 5 * sin (time);  tire.rz = - (tire.tx * (360.0 / (2 * )));

MEL Scripts  All MEL commands must terminate with a semicolon  A MEL script file (*.mel) is a file that contains MEL commands, MEL procedures, or both.  A MEL script is used to execute a sequence of commands.  When you execute a MEL script, it does not become part of the scene; you must execute the script each time you want to repeat the action.

Where are the scripts?  By default, Maya looks for your MEL scripts in your scripts directory.  By default, this location is  maya\6.0\scripts

Where is the Script Editor?  Open by selecting Window > General Editors > Script Editor  Click (the Script Editor icon) at the bottom right of the Maya window

Edit Commands in the Script Editor Win CmdMac CmdDescription Ctrl+cApple+c Copy Ctrl+xApple+x Cut Ctrl+vApple+v Paste Ctrl+aApple+a Select all the text in the edit box

Opening a script  Opening a script doesn't execute it. It simply displays the script in the input section of the Script Editor.  To execute some or all of a script displayed in the input section of the Script Editor, highlight it with your mouse press your keyboard's numeric Enter key.

Sourcing a script  Sourcing a MEL script file executes all of the MEL commands and declares all global procedures that are contained within the script file.  If you modify a procedure in a script file, Maya will not register the changes to that procedure until you source its script file. This is because Maya keeps executed procedures in memory.

Executing a script  Enter the script name in the command input (bottom portion) of the Script Editor and do one of the following: press Ctrl + Enter press the Enter key on the numeric keypad select Edit > Execute from the Script Editor  If no part of the MEL script definition fails, then the definition is moved from the bottom portion to the top portion of the Script Editor.

MEL Scripts  All MEL commands must terminate with a semicolon  A MEL script file (*.mel) is a file that contains MEL commands, MEL procedures, or both.  A MEL script is used to execute a sequence of commands.  When you execute a MEL script, it does not become part of the scene; you must execute the script each time you want to repeat the action.

time -A Predefined Variable in Maya NOTE: the following table assumes a frame rate of 24 fps. FrameTime (seconds)

Sourcing a script  When you source a global MEL script, global procedures are declared.  If you declare a local procedure by entering it in the Script Editor or Command Line, the procedure is declared globally and you can execute it at any time.

Hotkeys  If you use a menu selection frequently, you may want to assign it to a hotkey.  You assign hotkeys in the Hotkey Editor (Window > Settings/Preferences > Hotkeys) window.  You can assign hotkeys to your own MEL scripts or to commands that accompany plug-in software.

How Hotkeys Are Saved  Maya saves your custom hotkey preferences so that they do not interfere with the default Maya hotkey settings.  Your preferences will not be overwritten when you upgrade to the next Maya version.  The file names containing hotkey preferences are userHotkeys.mel and userNamedCommands.mel under user prefs directory: