Maya Embedded Language

From Wikipedia, the free encyclopedia

The Maya Embedded Language (MEL) is a scripting language used to simplify tasks in Autodesk's 3D Graphics Software Maya. Most tasks that can be achieved through Maya's GUI can be achieved with MEL, as well as certain tasks that are not available from the GUI. MEL offers a method of speeding up complicated or repetetitive tasks, as well as allowing users to redistribute a specific set of commands with others that may find it useful.

MEL is syntactically similar to Perl. It provides some memory management and dynamic array-allocation, and offers direct access to functions specific to Maya.

1 Applications of MEL
2 References
3 See also
4 External links

[edit] Applications of MEL

The tools designed using MEL Scripts generally come under the following categories.

• Data I/O

• Motion capture data import

• Proprietary game data export

• Scene meta-data for production tracking

• Geometry creation/modification

• Custom primitives

• Third-party renderer specific data type (e.g., RenderMan sub-divisional surfaces)

• Modeling tools not offered in the base package

• Animation tools

• Muscle simulators

• Rigging/setup controls

• Crowd AI behavior

• Lighting /rendering tools

• Automatic creation of common complex Shader setups

• Pre- and post-render effects

• Making calls to third-party renderers

• Dynamics

• Custom particle behavior

• Cloth simulation

• User interface customization

• Custom character controls

• Removal of invalid Maya commands

• UIs for a tool

This is an example of a script which copies a selected object through its path:

 // animated duplicate/instance script
 proc animatedDuplication(int $rangeStart, int $rangeEnd,
                          int $numOfDuplicates, int $duplicateOrInstance){
   int $range_start = $rangeStart;
   int $range_end = $rangeEnd;
   int $num_of_duplicates = $numOfDuplicates;
   int $step_size = ($range_end - $range_start) / $num_of_duplicates;
   int $i = 0;
   int $temp;

   currentTime $range_start;     // set to range start

   string $selectedObjects[];    // to store selected objects
   $selectedObjects = `ls -sl`;  // store selected objects
   select $selectedObjects;

   while($i <= $num_of_duplicates) {
     $temp = $range_start + ($step_size * $i);
     currentTime ($temp);
     // seleced the objects to duplicate or instance
     select $selectedObjects;
     if($duplicateOrInstance == 0) {
       duplicate;
     } else {
       instance;
     }
        $i++;
   }
 }

 // Usage example:
 //  duplicate the current selection 5 times -- 
 //  evenly distributed between frame 1 and 240
 animatedDuplication(1, 240, 5, 0);

Maya also offers an expression language that is a superset of MEL, and results in nodes that are executed as part of Maya's dependency graph. Expressions are developed with Maya's expression editor, and allow scripts to act while Maya evaluates the scene file, to simulate complex behaviors or perform other useful tasks.

[edit] References

Mark R. Wilkins, Chris Kazmier: "MEL Scripting for Maya Animators"
- 1st, Morgan Kaufmann 2002; ISBN 1-55860-841-9
- 2nd, Morgan Kaufmann 2005; ISBN 0-12-088793-2