MEL Command to grab object's name?

[chiggins]

I have an expression on an attribute and I need a command that will grab that object's name, so that I can then put its name into a string.

This has got to be an easy one, but I haven't found it yet.

Anyone know what I should use?

Thanks,

-chiggins

[joojaa]

Actualy, its bit tricky. I mean if the objecst name is known in advance its simple. But the porblem is that a node isnt supposed to know its place in the dg, so the node itself does not know who it is.

It would be nice to know exactly what you are trying to accomplish because you threading in a area thats realy realy slippery so to speak. Also unless you actualy know what your doing then your going to get into real trouble with this, because your actualy kindoff breaking the cornerstone maya is built on. (the hardest possible scenario comes if you everreference it in wich case youll realy start to appriciate other ways of doing this)

If you actauly refeer to your earlier post then theres a lot of things that do dictate that it is indeed a VERY VERY bad idea. Because it would break many things of the entire idea behind expression evaluation! Note this is NO joke you can end up with huge performance and evaluation problems if you push this idea as it is now.

Instead what i propose is to once store the attribute in a container, and if theres a danger that the nodes change names in the future then use a scriptjob to update this.

List all scriptnodes and using ls -type expression and iterate thru them and do whatever need to be done. Its safer and performance wise about a few hundred times faster.

If you care to tell exactly what your doing then id be happy to develop a even better solution.

[chiggins]

Wow. I had no idea I was venturing into such dangerous water here.... all I thought I was asking Maya to do was to give me the name of an object. Why does that have to be so difficult?

I do appreciate your response, though, so let me explain:

I have 30 spotlights, all named spotLight1-spotLight30. Into each of these, I've created an integer attribute called .num (because I need that attribute and info for a MTOR shadowgen call). So, right now, I've just gone through and entered 1-30 into each light's .num, so that it corresponds with the light's number.

But as I proceed, I would like to have an expression in .num which does this for me automatically, as I duplicate more lights. To achieve this, I've written the following expression to return the last 2 numbers of a string:

int $result;
$result = endString("spotLightShape23", 2);
spotLightShape23.num = $result;

and that works great. But what I need is a call to the object's name so that this expression above is not spotLightShape23 specific, so that I don't have to manually change that to spotLightShape24, 25, etc.

Does that make sense?

[joojaa]

No just using expressions for this is abit wierd.

Okay you should understand that tehres a HUGE difference between a expression and MEL, its like night and day. Even their syntax differs, somewhat.

Expression nodes are however capable of running mel inside them, because they do kow the whole mel parser routine. That however does not mean you should call mel inside a a expression, infact you should abstain form doing so as much as humanly possible. Why should you avoid mel inside a expression?

[ul][*]it does not get connected to the dg, thereby depriving maya of any knowlege on how its related to the big picture.

[*]it is possible to break the inner workings of dg with a misplaced expression.

[*]It has a potential on being very very slow because its initiated outside rhe normal working of the dg, infact some melsyntax stuff like getAttr will force the graph to re evaluate, cusing a ppossibe extra loop, making maya do 2 times the work for each time its called.

[*]Nodes woud not be able to detect renaming, wich would lead to nonworking expressions if the element wads renamed or referenced. The node cat even realy rectify this because it does not know who it is. (a node should not know hwo he his by the way or anything of the big picture thats their entire purpose)

[/list]

Okay now in your case theres absolutely NO need for any of this! Its just pure stupid! just generate the data once. Your version generates the data for ech and everuffreame in esistence.

What you do is a mel loop, that is run on demand, that is ONCE when you have all your lights placed. A samle fragment of mel would look like this NOTE THIS IS NO EXPRESSION Its mel execute in the script editor:

{
string $spot;
$spots=ls -type spotLight;
for($spot in $spots){
// uncomment next 2 lines if you need thetransform to host this, not shape
// altough shape is more likely for mtor
// $spotTemp=listRelatives -parent $spot;
// $spot=$spotTemp[0];
$end=match("[1234567890]*$", $spot);
if (!(attributeExists "num" $spot)){
addAttr -ln num -at long -dv ((int) $end) $spot;
}else
setAttr ($spot+".num") ((int) $end);
}
}

offcourser now it wouldnt do this automaticaly, but it could you could either set tjis a s a prerender script of somekind OR make a scriptjob to watch the change of names. But it so happens you dont need this.

In MTOR theres realy no need for this mtor can handle it on push to rendertime jut like a prerender script, wich makes it even easier. before render mtor parses trough a tcl script that is run, the variable $OBJNAME contains the name of the object in question. Now with a bit of tcl you can easily derive the end off the objname... But thats more of a topic for a tcl forum. Read your MTOR manual and then a tcl manpage.

Edity made the script a wee bit more roboust.[/ul]