Mel

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Mel Hot Keys

• Review

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Whats MEL?

• Maya Embedded Language
• Most of Maya's interface is built using MEL
  commands and scripts.

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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.

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MEL in the Expression Editor

• translateY ball.translateZ
• Or
• ty ball.tz
• ball.tx 5 sin (time)
• tire.rz - (tire.tx (360.0 / (2 3.1415)))

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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.

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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

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Where is the Script Editor?

• Open by selecting Window gt General Editors gt
  Script Editor
• Click (the Script Editor icon) at the bottom
  right of the Maya window

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Edit Commands in the Script Editor
Win Cmd Mac Cmd Description Ctrlc Applec Copy Ct
rlx Applex Cut Ctrlv Applev Paste
Ctrla Applea Select all the text in the edit
box
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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.

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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.

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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 gt 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.

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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.

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time -A Predefined Variable in Maya NOTE the
following table assumes a frame rate of 24 fps.
Frame Time (seconds)
0 0.0
1 0.0417
2 0.0833
3 0.125
24 1.0
240 10.0
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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.

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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 gt
  Settings/Preferences gt Hotkeys) window.
• You can assign hotkeys to your own MEL scripts or
  to commands that accompany plug-in software.

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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