Mel Libraries

[doug-hines]

I am attempting to create several MEL scripts that can be called from a menu such as this example I came across in the forums

CODE
global string $gMainWindow;
    setParent $gMainWindow;
    menu
    -label "Test Menu in Main menu"
    -parent $gMainWindow
    -tearOff on;
    menuItem
    -ann "This is a test menu"
    -label "This is a test menu"
    -echoCommand true;

My problem however is that I do not quite understand the differences between a .mel and .mll file types or even where to put them. What I do understand is that a .mll file can be auto loaded through the plugin manager. I do not however know how to call the seperate scripts.

I would like to design these scripts to be loaded from a folder located inside the drive:/programFiles/Maya/scripts/ folder.

Any information on this subject would be most appreciative.

[kurianos3d]

Oke first mel is open source you can read and modify the script but mll is plugin its compiled and its can read onl b maya its in binary format its a tpe of dll file . if ou want load an mel script you cn usesource command and if you want to load any plugin you can use loadplugin command

and if you want customized script and plugin folders then maya hainga file maya.env this u can find in c:\dcumnts\user\mydoc\maya\maya8.0\maya.env

open that and add SCRIPT_PATH = "your scriptpath"
PLUGIN_PATH="our plugin folder"

and for sourcing all mel in highend 3d itsself lot of scrtipts is there check that

o.S.k

[daniel-faust]

IN 99% of the cases it is irrelevant for a script where it resides, the only important thing is that the path to the folder where this script resides is in the MAYA_SCRIPT_PATH. Some folders like the one you mentioned are automatically recognized by maya, you can add others by adding the following line in the Maya.env file:
MAYA_SCRIPT_PATH=C:/App/Maya6.0/devkit/plug-ins;C:/App/Gelato/mango/maya6.0/scripts;

Don't forget to source the mel files you want to use. Mel files are automatically sourced if 1) their filename matches one of the functions it contains and 2) maya makes a call to that function.

mll files are a different story. mll's are actually dll's with the first letter changed to indicate that they work with maya, it's just a naming convention. These dlls are not written in mel but in c++, which is a bit more difficult to set up and use for beginners. Usually when you hear something about API then it's about developing an mll file in c++ (but now with maya 8.5 the API can also be used from python, another programming language)

[doug-hines]

Ok, I understand about .mll files. I'm still a tad fuzzy on sourcing .mel files though.

From what I have read in the help manual and from what has been posted online, if I simply name the file the same as a command/proc, then that script file will be called without errors?

All I have to do is open up the maya env file, add the line :

MAYA_SCRIPT_PATH=drive:/path/to/my/main/script;

Is there a way to do this when I first run the script? I would prefer the use not to have to mess with or hunt down files on their hard drive.

[daniel-faust]

then place your script inside C:\Documents and Settings---\My Documents\maya\6.0\scripts
this is also one fo those special folders where you don#t have to change the environment variable.

if your mel file has a different name that all the functions in it, you can explicitly load the file with the "source" command.

[joojaa]

QUOTE(Daniel_Faus @ 03/03/07, 11:11 AM) [snapback]261350[/snapback]
if your mel file has a different name that all the functions in it, you can explicitly load the file with the "source" command.

Actually if you call:

myMel();

3 things happen.

Maya checks the memory to see if such a proc is loaded, if so it executes it and terminates here

The list of files in the hash (maya reads the defined list of directories this once on startup and puts it in a hash) is searched for a file named myMel.mel, if it finds this file it sources it if and only if that file was not already sourced

If that file contained a proc named myMel and it has no arguments maya executes that proc.

Now this has a surprising side effect. IF the file has no inpoint in this case a proc named myMel then nothing will happen by calling myMel, except on the first time its called. This is because sourcing actually executes the code in the file, so if theres any commands outside proc declarations they get executed. But only at first call the second time maya knows theres no such proc.

Ok, Mll's don't get automatically loads either, just the ones in mayas auto load list. Actually theres a second variable in maya that defines wich paths to look for mll files and loading them is totaly comparable to mel sourcing (maya will find them if it needs them as long as they are in the plugin path).

NOW it is possible to let ypur scripts and plugs reside anywhere on the drive but then you will have to explicitly tell maya the full path to the files.

BTW This works just like a command shell would work bat and exe files. Like ive been telling you try to understand command shells a wild 50% of everything you ever do is actually a a offshoot of this,

[f117f117f117677]

QUOTE(Joojaa @ 03/03/07, 01:26 AM) [snapback]261351[/snapback]
BTW This works just like a command shell would work bat and exe files. Like ive been telling you try to understand command shells a wild 50% of everything you ever do is actually a a offshoot of this,

what do these sentences mean?

BTW?

[doug-hines]

Ok, I understand this now. I will have to figure out a way to add the script path to the maya env file automatically. Maya didnt like the fact that the file was located 1 folder below the script file

.../maya/7.0/scripts/filefolder/file.mel

If I wanted to auto source this mel file every time Maya started, would I need to add a source file.mel command to the maya.env file?

[daniel-faust]

maya.env doesn't know mel, so you can't issue mel commands in there and therefore can't source a file. You can only set environment variables in that file.

[doug-hines]

QUOTE(Daniel_Faus @ 03/03/07, 06:52 AM) [snapback]261375[/snapback]
maya.env doesn't know mel, so you can't issue mel commands in there and therefore can't source a file. You can only set environment variables in that file.

So is there no way to auto source a mel script on start up? Am I going to have to learn the API to simply create a menu plugin?

[daniel-faust]

place a file called userSetup.mel in the folder C:\Documents and Settings---\My Documents\maya\6.0\scripts\

this will be sourced automatically at startup. In that file you can issue a "source" command which then sources your file to which you specify the full location.

This userSetup.mel file was used by alias to include their bonus tools upon startup (to build the menues), and by other tools like the spacemouse. So this might be the place where you want to add your stuff.

[doug-hines]

ok, userSetup.mel inside my ../maya/7.0/scripts folder has the following code

CODE
source "E:\Documents and Settings\Administrator\My Documents\maya\7.0\scripts\Marionette\marionette.mel";

But when I launch maya, the menu doesnt appear.

[joojaa]

Therese a precedence in maya env files.

so if the env contains folders

a b c d and e maya proceeds to check the files in reverse declaration order, so if theres 2 userSetup. mels the one in lower precedence never gets executed.

[doug-hines]

So should I go through and delete the userSetup.mel files and maya.env files on my system.

[daniel-faust]

No, you should just add a line to userSetup.mel which sources your other files.

Look, in one of the paths which are specified in the maya.env file, for example in c:/my/mel/files, which is specified as MAYA_SCRIPT_PATH=c:/my/mel/files;c:/this/was/already/there;, in that path you place a file called marionetteSetup.mel

this file c:/my/mel/files/marionetteSetup.mel contains the following lines:

CODE
global proc marionetteSetup() {
  print("marionette setup started.");
  buildMarionetteSetup();
}

global proc buildMarionetteSetup() {
  //...
  print("marionette menu successfully built.");
}

Now, if you find a file called userSetup.mel in the path C:\Documents and Settings---\My Documents\maya\6.0\scripts\, then open that file in an editor and append the line marionetteSetup(); to that file. If it does not exist, then create it and place that single line of code into that file. In the future you can write a small mel cript whihc automatically opens or creates that userSetup.mel file and appends the line of code automatically, so that your users don't have to open it in a text editor and edi that file manually.

[joojaa]

Look its really simple you should sit down and think for a moment. Draw on paper or whatever works for you.

This is computer technology form early 1970's btw, just because you dont see the inner workings day to day- I mean the foundations put in place in the beginning will affect your life every day use for the computer. Compueter use dont get much more fundamental than this, this is the basis for almost everything the computer does.

Think of how you work in real world:

If you need a screwdriver, you go and search the screwdriver form the toolbox, if you dont find i there you go and look for it on in the garage first on tables and floors.... when you find it, you stop searching. Even if you had 20 screwdrivers you search only for one thet fills the description and terminate after this.

now what the hell is the env file? Its just the list of things that you can search for, and instructions on how to search for them. (so its a lists of items which are a list of places to look for screwdrivers).

EXTRA course:

To complicate this a bit further its actually chained. Theres not just one ENV file theres many. They get appended to each other. (why is there many places you can set things, well lets suppose you are a computer operator in system that manages the entire telephone system chain of the world, its impossible for you to manage it all by yourself, however you don't have to you just manage one region and let others manage whats outside o this). So the env file is most likely pace to find something.

NOW its really really important that you know where the FIRST instance of said file in the list is if theres 2 of them only one EVER gets called unless you implicitly call both with full pathnames.

However you can ask maya wich file is the one it reads by asking it.

whatIs userSetup.mel;

and maya will tell you:

C:/some/folder/with/scripts/userSetup.mel

NOW userSetup.mel is jut one file that gets always called when you start up this is whre you should put all your customizations.

NOW the mlls arent autodoaded, they are autoloaded becaus etheres a mel file that does it.

Again when maya gets started only one mel file gets loaded! however this mel file calls all the other files. INcidenttaly this file also loads a file taht autolads the plugins too.

One of the last things it does is calls userStup.mel so taht you can make yoru own customisations

PS. you will bash heads forever if you dont exactly understand how this works. Especially if you dont know how the OS environment works because you will need it if you ever do anything more involved