Maya Embedded Language - AbsoluteAstronomy.com

The Maya Embedded Language (MEL) is a scripting language used to simplify tasks in Autodesk's

Autodesk

Autodesk, Inc. is an American multinational corporation that focuses on 3D design software for use in the architecture, engineering, construction, manufacturing, media and entertainment industries. The company was founded in 1982 by John Walker, a coauthor of the first versions of the company's...

3D Graphics Software Maya

Maya (software)

Autodesk Maya , commonly shortened to Maya, is 3D computer graphics software that runs on Microsoft Windows, Mac OS and Linux, originally developed by Alias Systems Corporation and currently owned and developed by Autodesk, Inc. It is used to create interactive 3D applications, including video...

. Most tasks that can be achieved through Maya's GUI

Gui

Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...

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 repetitive tasks, as well as allowing users to redistribute a specific set of commands to others that may find it useful.

MEL is syntactically similar to Tcl

Tcl

Tcl is a scripting language created by John Ousterhout. Originally "born out of frustration", according to the author, with programmers devising their own languages intended to be embedded into applications, Tcl gained acceptance on its own...

and Perl

Perl

Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...

. It provides some memory management and dynamic array-allocation, and offers direct access to functions specific to Maya. The majority of standard Maya commands are default MEL scripts, saved in the Maya Program Files directory.

MEL is fairly limited compared to mainstream scripting languages. It is not object oriented, and lacks advanced features such as associative arrays. Very few improvements have been made to it in recent years, and in Maya 8.5, Python

Python (programming language)

Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...

was added to Maya as an alternative to MEL.

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
Simulated object emergent flocking and swarming
Genetic algorithms
Cloth simulation
File and Folder Scene Setup and Maintenance
User interface customization
Custom character controls
Removal of invalid Maya commands
Custom UIs

Example

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



// animated duplicates/instances 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);

Expression Language
Maya also offers an expression language that is a super-set 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 trigger while Maya evaluates the scene file at each change in time, to simulate complex behaviors or perform other useful tasks.
External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Applications of MEL

Example

0) { duplicate; } else { instance; } $i++; } }

0)
{
duplicate;
}
else
{
instance;
}
$i++;
}
}