how to query if an object exists

[mark_wilkins]

string $matchingNodes[] = `ls Rt_armJNT`;

// The following relies on Maya treating integers
// that are nonzero as true and zero as false,
// so if size($matchingNodes) is more than one
// it's true and if it's 0 it's false:

if (size($matchingNodes)) {
// if you get here, Rt_armJNT exists
}
else {
// if you get here, it doesn't
}


Note that if you had the name of a node for which you wanted to test in a string variable, you could do it like this:


string $mynodename = "Rt_armJNT";
string $matchingNodes[] = `ls $mynodename`;

if (size($matchingNodes)) {
// if you get here, the node whose name is in $mynodename exists
}
else {
// if you get here, it doesn't
}

[mhovland]

Try this

if(`objExists Rt_armJNT`)
{
//do stuff here
}
else
{
warning ("object Rt_armJNT does not exist in the scene.");
}

[rusted_nut]

thanks gentlemen,

your responses are appreciated

[mark_wilkins]

Heh. I guess most of the time I'm checking for the existence of a number of objects and I get the list at the same time with a wildcard like


string $myJoints[] = `ls "*JNT"`;


so I just plain forgot about the objExists command.

You can use wildcards in objExists also, if that's useful or convenient for you:


if (`objExists "*JNT"`) {
//whatever
}


-- Mark

[klod]

hi,

yes, objExists is a nice function.

I use it also to check if an attribute exists:

string $myNode = "justANode";
if (`objExists ($myNode + ".myAttribute")`)
// whatever
else
// whatever too


Klod

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