Basic MEL Question #1

[mrwolfy]

how do I select a specific node? For instance here I have a cloth object in which I want to change the "rigidity".

ls -sl;
polySurface515 (geometry)
nCloth129 (the cloth shape node that contains the .rigidity attribute)

I need to do this to many objects so I want to write a script that changes the rigidity of the selection set of all of these objects. so how do I select only the cloth, so that I can cycle through and change the value?

[norbert-nacu]

Hi There,
    I wrote a simple script to do that task, so if you want to change all the nCloth attributes in your scene, please DON'T select anything.  If you want to change a single node, please select ONE mesh node. 

// COMMAND
// ChangeClothRiggidity( ATTRIBUTE, VALUE );
// ie...
ChangeClothRiggidity( "rigidity", 10  );

global proc int ChangeClothRiggidity( string $attrib, float $value )
{
string $selNodes[] = ls -sl -l -dag -typ "mesh";
string $clothShapes[];

if( !size( $selNodes ) )
{
$selNodes = ls -l -typ "mesh";
}

for( $selNode in $selNodes )
{
string $cons[] = listConnections -t "nCloth" $selNode;
if( size( $cons ) )
{
if( !stringArrayContains( $cons[0], $clothShapes ) )
{
$clothShapes[size( $clothShapes )] = $cons[0];
}
}
}

if( !size( $clothShapes ) )
{
warning( "Unable to find clothShape nodes" );
return true;
}

float $increment = 100 / ((float)size($clothShapes));
float $progress = 0;
progressWindow -t "Processing..." -pr ((int)$progress) -st "Progress: 0%" -ii 1;

for( $clothShape in $clothShapes )
{
$progress += $increment;
progressWindow -e -t $clothShape -pr ((int)$progress) -st ("Progress: " + ((int)$progress)+"%");

if( progressWindow -q -ic )
{
break;
}

setAttr( $clothShape + "." + $attrib ) $value;
}

progressWindow -ep;

return false;
}

Thank You,
Norbert Nacu

[sam-klock]

Quick question, are you wanting to change them all to the same value? So you want something to have 5/10 cloths selected and want those 5 to all have the same rigidity? Then select 3 more and set those all to the same rigidity? If so:

global proc nClothMassRigid(float $amount)
{
string $mesh, $meshes[], $cloth[];

$meshes = `ls -sl -dag -exactType mesh`;

if (!size($meshes)){
	error "Please select some Geometry";
}

for ($mesh in $meshes){
	$cloth = `listConnections -t nCloth $mesh`;
	setAttr ($cloth[0]+".rigidity") $amount;
}

}

[sam-klock]

Quick question, are you wanting to change them all to the same value? So you want something to have 5/10 cloths selected and want those 5 to all have the same rigidity? Then select 3 more and set those all to the same rigidity? If so:

global proc nClothMassRigid(float $amount)
{
string $mesh, $meshes[], $cloth[];

$meshes = ls -sl -dag -exactType mesh;

if (!size($meshes)){
error "Please select some Geometry";
}

for ($mesh in $meshes){
$cloth = listConnections -t nCloth $mesh;
setAttr ($cloth[0]+".rigidity") $amount;
}
}

Basically if you want to select a specific node there is a few ways to do it, one is to select the node yourself(hypergraph or outliner) and do "ls -sl -dag -showType" which will return the name and then the node type. Then when you execute your script use this command to populate your selection array "ls -sl -dag -exactType 'node type'". Node type does NOT have to be in quotes, but depending on who you talk to will tell you it is better code if it's in or not in quotes.

The other is the listConnections route. In my example script I used listConnections. Should you ever want to get more specific with your flags(may be needed depending on your scene) look at the documentation. I usually throw in a -source or -destination flag just to be safe.

Which way you approach this problem is dependent on your scene and your dag.