MEL: Check If An Object Or Attribute Exists

Ever needed to check if an object exists in your Maya scene? Or perhaps you need to check if a certain object has an attribute or not?

Use the objExists mel command.

First let's use it in a simple way to check for the existence of an object saved in $myObject

// objExists will return true or false (1 or 0), so you can use it multiple ways.
int $objTest = `objExists $myObject` ;

// If that object exists, it will return 1 (true), so then you could say something like:
if($objTest == 1) {
 print "It Exists!" ;
}

// Another trick you can do is an IF statement will simply test a boolean (true or false) and fire if it's true, example:
if($objTest) {
 print "It Exists!" ;
}

// So using that, we can simply test for the return of objExists in our IF statement, to simplify it even more.
if(`objExists $myObj`) {
 print "It Exists!" ;
}

This works for attributes too, so to check for the existence of an attribute on a certain object, let's say "R_Arm_Ctrl.IKFK" we can use the following:

if(`objExists "R_Arm_Ctrl.IKFK"`) print "It Exists!" ;

Huzzah!

MEL: Print Size Of Your Current Selection, Or Print Your Current Selection

There are a few different ways to print out the size of your selection.

To print the size of your selection:

// Simply use the size command combined with the return of the list selected command
size(`ls -selection`) ;

To print what is currently selected:

// Use the LS command to list your selection
ls -selection ;

// Or print it... (same thing)
print `ls -selection` ;
// What about vertices? (faces, etc.)
// ls -selection ; will usually return a next to useless result with multiple verts selected.
// Instead add another flag, -flatten
ls -selection -flatten ;

Any questions? Please comment below.