The Main Event - event oriented programming in Maya

The Maya Callbacks Cheat Sheet post started out as an effort to explain the design the event system in mGui - but it quickly turned into it's own thing as I realized that the vanilla Maya system remains confusing to lots of people.  With that background out of the way, I want to return to events proper, both to explain why they work the way the do in mGui and also how they can be useful for other projects as well (I use them all over the place in non-GUI contexts).

...and, because it's got the word 'event' in it, I'm going to throw in a lot of irrelevant references as I can manage to The Crushah!

Maya callbacks cheat sheet

Update 5/7/14: Added a note on closures and lambdas

In All Your Base Classes,  I suggested that we can do better than the standard callback mechanism for doing Maya event handling.  The limitations of the default method are something I've complained about before, and if you follow these things on TAO or CGTalk or StackOverflow it seems pretty clear that a lot of other people have problems with the standard Maya code flow too.

I was planning on devoting the next big post to the event mechanism in mGui . However as I did the spadework for this post I decided it was better to split it up into two parts, since a lot of folks seem to be confused about the right way to manage basic Maya callbacks. Before moving fancy stuff, it's a good idea to make sure the basics are clear. Most vets will already know most of what I'm going over here, but I found the  time spent laying it out for myself a useful exercise  so I figured it would be worth sharing even if it's not revolutionary.

Classic CG: La plus ca change

From SIGGRAPH 1992.



While I'd hesitate to call this a 'classic' it does prove one thing: tacky me-too crap is eternal  Hands up if you remember palette animations!  (For that matter, walkers and canes up if you remember the local-cable ads this thing was parodying!)

Roger Roger

If you've been playing with the stansdaloneRPC server, I've added a new branch to the github project that includes a minimal level of password security. It's still not the kind of security you want if this is to be exposed to the wicked world, but it should suffice to keep you free from teammates who want to prank you.

Comments / bug reports and pull request welcome!  If you use the github wiki to log an issue or ask a question, it's a good idea to put a comment here to make sure I see it.

Sweet Sumotori Dreams

I had no idea that the genius behind Sumotori Dreams is still making awesome procedural animation toys.

If you're not familiar with Sumotori Dreams, it's the funniest thing that ever happened to procedual animation.  Proof here (loud cackling and some profanity in the audio track, could not find any that did not have lots of hilarity and shouting):

If you're at all interested in procedural animation - or have even a tiny sliver of a sense of humor - you should buy the iPhone app the android app, or the PC version.  This guys deserves our support!

On a related note, if you like this you may find this talk from the developer of Overgrowth interesting as well.

Warning: Garish graphics ahead!

If you're tired of boring old light-grey-on-dark-grey text, you'l'l be pleased to know that the Maya text widget actually supports a surprising amount of HTML markup. Which means that instead of this:

You set peoples eyeballs on fire like this:

This is a single cmds.text object  with it's  label property set to an HTML string.  

Mighty Morphin Module Manager Made Moreso

I've added a port of the Maya Module Manager I posted a while back to the examples included with the mGui maya GUI library.  This was an exercise to see how much the neater and more concise I could make it using the library.

Here's some interesting stats:

The original version was 237 lines of code, not counting the header comments. The mGui version was 178 without the header, so about 25% shorter overall.  There are about 80 lines of unchanged, purely behind-the-scenes code which didn't change between versions, so the real savings is more like 45%.   Plus, the original sample included some functions for formLayout wrangling  so real savings might be a little higher for more old-fashioned code.

Like I said last time, the mGui package is still evolving so it's still very much in a "use at your own risk" state right now... That said, I'd love to get comments, feedback and suggestions.

Earth calling maya.standalone!

Somebody on Tech-artists.org was asking about how to control a maya.standalone instance remotely.  In ordinary Maya you could use the commandPort, but the commandPort doesn't exist when running under standalone - apparently it's part of the GUI layer which is not present in batch mode.

So, I whipped up an uber-simple JSON-RPC-like server to run in a maya standalone and accept remote commands. In response to some queries I've polished it up and put it onto GitHub.

It's an ultra-simple setup. Running the module as a script form mayapy.exe starts a server:

    mayapy.exe   path/to/standaloneRPC.py

To connect to it from another environment, you import the module, format the command you want to send, and shoot it across to the server. Commands return a JSON-encoded dictionary. When you make a successful command, the return object will include a field called 'results' containg a json-encoded version of the results:

           
        cmd = CMD('cmds.ls', type='transform')
        print send_command(cmd)
        >>> {success:True, result:[u'persp', u'top', u'side', u'front'}
 

For failed queries, the result includes the exception and a traceback string:

           
        cmd = CMD('cmds.fred')  # nonexistent command
        print send_command(cmd)
        >>> {"exception": "", 
             "traceback": "Traceback (most recent call last)... #SNIP#",
             "success": false, 
             "args": "[]", 
             "kwargs": "{}", 
             "cmd_name": "cmds.fred"}
 

It's a single file for easy drop. Please, please read the notes - the module includes no effort at authentication or security, so it exposes any machine running it to anyone who knows its there. Don't let a machine running this be visible to the internet!

Classic (?) CG: Bingo the Clown

From the Classic CG files comes Bingo the Clown. This was originally created to showcase the capabilities of Maya 1.0, back in 1998. It creeped me out then and it creeps me out now.




I've been told, I don't know how correctly, that Chris Landreth - the animator who did this film - was the driving force between Maya's decision to use Euler angles for everything. I hope that's not true. Having this video and those goddamn Euler angles on your conscience is a lot to answer for.