Create a MEL procedure for collision events

To use an event procedure with collision events, your MEL script containing the procedure must have the following format and argument list:

global proc 
myEventProc
 (string 
	 
$particleObject
, int 
	 
$particleId
, string 
	 
$geometryObject
) { 
	 
Type MEL statements here;
} 
  

Where,

• myEventProc is the name of the MEL procedure and the script.
• $particleObject is the name of the particle object that collides with the geometry.
• $particleId is the particle id of the particle that collides.
• $geometryObject is the name of the geometry.

When you create an event procedure, be aware of following:

• You do not need to use the contents of the arguments in your procedure, but they must exist in the procedure definition.
• Name the MEL file the same as the procedure so that the procedure is loaded into memory when you source the script.
• To have your script and its procedure sourced each time you start Maya, put the MEL script in your Maya project’s scripts folder. For example, Maya\<version>\scripts\.

To add the script procedure to a particle collision event

1. Open the Script Editor by selecting Windows > General Editor > Script Editor.
2. In the Script Editor select File > Source Script to source the script that contains the procedure.
   Note:

   If the procedure creates objects, Maya does not delete them when you rewind your simulation. You can also source a procedure without sourcing the script that contains it. See MEL and Expressions for more details on working with scripts and procedures.

3. in the FX menu set, select nParticles > Particle Collision Event Editor.

   The Particle Collision Event Editor appears.

4. In the Particle Collision Event Editor do the following:
   • Click Create Event.
   • (Optional) Turn on Original Particles Die if you want the source particle object to die after the collision.
   • Type the name of your event procedure in the Event procedure field.