Pinkwerks.com

Bayes and the Lost AIMA Lisp

pink — Mon, 02 Jan 2012 15:41:13 +0000

So I found myself surfing the tubes, looking for code examples of Bayes networks written in Lisp to compliment my recent studies for Stanford’s online ‘Introduction to Artificial Intelligence’ course… because that’s what I do for fun.

An obvious stop would be the main code repository for the AIMA book. Surprisingly that place doesn’t have anything at all to deal with Bayes networks. Or does it? I smell adventure.

After a fair amount of digging I’ve come across some Lisp code from one of Stuart Russell’s A.I. classes at Berkeley that I’d like to share with you, via the way-back machine.

http://wayback.archive.org/web/*/http://www-inst.eecs.berkeley.edu/~cs188/code-188.ZIP

Interestingly I found more than a few files in the catacombs that aren’t in the main repository or possibly very different. Some nuggests include bayes-nets.lisp, elimination.lisp, probability.lisp, sampling.lisp, and statistics.lisp.

Eureka! I’ve found the ancient artifacts and my journey is near completion. However I was haunted by my own conspiracies of why they were lost to the internet archive to begin with.

So, recalling Occam’s Razor, I decided to mail Peter Norvig and see what he had to say about it. This was his reply. ‘Yes, Stuart did some code for various versions of the course, and he meant to integrate them bacj into the main branch but never did…’

Case closed.

My 2011 Visual Effects Demo Reel

pink — Wed, 13 Apr 2011 03:45:55 +0000

I present my 2011 VFX Demo Reel with all new content.
Pinkreel 2011. 113MB. HD720p. 24fps. 3:03. H.264. Help from many. Music by Plaid.
High resolution version of the above picutre.
It’s been a few years since my 2007 demo reel, I hope you enjoy it.

You can find a detailed list of my responsibilities for the various spots on my resume page. Plus I’m happy to discuss ‘how we did it’. That’s the fun part.

This was edited on my Debian Linux 6.0 “squeeze” distribution (64-bit) with Kdenlive. I used Quicktime compressed with JPEG maximum quality for the intermediate codec from original source material. Running on an Intel Core i7 CPU. The playback was pretty amazing. This is why I donate to free and open source software and you should to.

Bash manipulation on sequences.

pink — Mon, 11 Apr 2011 14:54:56 +0000

I’m going to come at you today with a very common situation. Renaming a series of files, bash and GNU utils style. This applies to something as trivial as importing my camera photos which typically gives me a bunch of files named IMG_2042.JPG, IMG_2043.JPG, IMG_2044.JPG and so on. I’m here to show you how to deal with that.

We’re gonna tackle this ground up. Firstly, I need a way to increment a number. seq is our tool.

seq -f %04g 1 3 0001 0002 0003

Sexy huh? We’ve already have a major building block right here. Let’s dissect this quickly. The ‘-f’ tells seq that we want a specially formatted list of numbers. In our case, zero padded numbers, at least 4 wide (%04). The letter ‘g’ gets replaced the current number in the following range (1 thru 3 in our case). If you don’t have padded numbers you can omit the use of ‘-f %04g’ altogether. The last two arguments are the range to start and end.

seq 1 3 1 2 3

Sweet, now we have way of representing pretty much any sequence of numbers, thanks seq! Now let’s tackle looping over this sequence of numbers and use them for renaming using a simple ‘for’ loop. In our case below the letter ‘n’ will get the results of the seq command.

for n in $(seq -f %04g 2042 2044) ; do mv IMG_$n.JPG utah.$n.jpg ; done `IMG_2042.JPG' -> `utah.2042.jpg' `IMG_2043.JPG' -> `utah.2043.jpg' `IMG_2044.JPG' -> `utah.2044.jpg'

That one-liner is so unbelievably flexible (replace `mv’ with `cp’ or `ln’ for instance) it will probably be your number one oft used idiom while working with bash in production. As a matter of fact, pretty much every thing I do is looping over a list of things – yum, sounds lispy.

I’ve always found this to be a great (re)read. In the beginning was the command line. It’s a zip archive, with an ol’ fashioned text file for you to read authored by Neal Stephenson.

Maya and Python and menus oh my!

pink — Fri, 04 Mar 2011 23:35:08 +0000

Updated, was, “Multiple Python commands with Maya’s menuItem MEL”

Maya drives me nuts. I really wish I could spend my day in Houdini to see if it sucks less. Anyway, I digress. Python is awesome. Python’s integration with the rest of Maya is, well lacking.

I like to add my own ‘Pinkwerks’ menu to the main menu bar in Maya for ease of access to my favorite hacks. Turns out, you can’t add a custom menu to the main menu bar in Maya via userSetup.py as you would in userSetup.mel – It doesn’t seem to have access to the GUI when it’s evaluated during Maya’s start-up. Maybe someone can prove me wrong. So, I’m lamely forced to writing my own menu for the main menu bar with classic MEL which looks something like this.

global string $gMainWindow; setParent $gMainWindow; global string $gPinkwerksMenu = "Pinkwerks"; menu -label "Pinkwerks" -allowOptionBoxes true -tearOff true $gPinkwerksMenu; menuItem -label "My Fancy Command" -command "myFancyCommand";

Now, let’s bring the pain. You’ve written a Python script and you want to call that script from a menuItem (as in the last line in the above code). A couple of points.

If you write foo.py and put it in MAYA_SCRIPT_PATH it isn’t loaded automagically like a .mel. (You’ll recall that if you name a .mel with the same name as a global function, it’s automatically callable by Maya at run-time. For instance if you have a file ‘myNoise.mel’ in a directory in the MAYA_SCRIPT_PATH environment variable and it contains a function in the form of ‘global proc myNoise(…){…’ you can type ‘myNoise’ at the MEL prompt or script editor and Maya will ‘find’ it without having to source it first.

This means if you have a Python function ‘myPyFunk’ in foo.py (and it resides in your MAYA_SCRIPT_PATH) – you still have to ‘import foo’ before you can call foo.myPyFunk(). Trouble is, this is two steps, the ‘-command’ argument to menuItem won’t evaluate a newline, even if you try and escape the hell out of it. So instead of foolishly trying this:

*BAD CODE FOLLOWS*


menuItem -label "My Py Funk"

-c "python(\"import foo\nfoo.MyPyFunk()\")";

To work around this you can structure your commands like so:
*GOOD CODE*


menuItem -label "My Py Funk"

-c "python(\"import foo\");python(\"foo.MyPyFunk()\")";

One last method of calling Python scripts before I wrap this up. If you’re like me, you tend to write code in and external editor. In Maya, for ease of use you want something analogous to `source mySheet.mel’, which reloads the file and runs the main task. You can get away one-liner simple execution of python scripts like so from the Python prompt or script editor tab:

execfile("/home/pink/maya/script/foo.py")

This trick is achieved by adding the 2 lines below to the end of your .py. This assumes you wrap the guts of your script in a function named ‘doit()’. The Python interpreter will automatically call the function ‘doit()’ when it parses this file during the execfile(). Note in this case, anything you type in the foo.py will be evaiuated with exec, so I tend to wrap everything in a function and don’t leave any `raw’ python lying about.

def doit(): sel=ls(sl=1) for s in sel: ...
if __name__ == '__main__': doit()

Unfortunately this process is less clean than MEL in terms of ease of integration, but not so bad once you get over the ‘gotchyas’. Personally, I’m digging PyMEL.

Easy right?

XBOX Lips : Gomez spotlight

pink — Mon, 24 Jan 2011 05:42:38 +0000

Thought I’d show off some character designs I came up for an XBOX Lips commercial from a couple years back. I kept trying to name him ‘Gomez’, it didn’t stick and he was better known as “Lippy”. These 3D models were a study from a 2D design provided by the agency. He was a tricky guy to fit all those teeth into. The final one was produced as hybrid comp trick so that we could fit a huge mouth magically into a space smaller than the volume of his torso.

Shout outs to the ISZ and Sam Kieth!

“The Blue Door” – Long Beach, CA

pink — Sun, 19 Sep 2010 17:08:28 +0000

These photos are now online. Joey has been pestering me for years about these – here they are. The resolution is fair, and so is the stitching. If you click them you can zoom in and read the details in the larger ones.

These photos were taken just before Joey moved out of this place. Looking back, It doesn’t look like he had started much of the packing. The door is now white, on the south east corner behind the house next to the alley. Looks different in Google’s light.

View Larger Map

Getting to second base.

pink — Wed, 18 Aug 2010 04:29:36 +0000

Preparing to take a picture from second base at Yankee's Stadium

Well, I never played anything but softball when I was in 2nd grade or something, yet somehow I’ve managed to find myself on holy ground at second base in the new Yankee’s stadium. And the majority of my teachers never thought I’d get anywhere (except for Judy Hemphill).

If you’re wondering WTF, well let me explain. Apparently you can’t actually make a commercial starring the Yankees and film at the stadium. You have to take an awesome ferry to Staten, shoot them there and fill in the stadium later in post. So, somehow, I got to be the lucky guy let onto the field to take reference photography. Unfortunately, I couldn’t take a tri-pod out with me as the turf is worth more than the GDP of small countries or something.

Photo credit : Al Torres

New Job Description

pink — Sat, 10 Jul 2010 19:57:47 +0000

ONDCP "Tree Service"

Hi so what’s new with me? Well, I quit my post as CG Supervisor at Method NY and I’m going back to being a freelancer. I’ve had a very proud 2.5 years there. Leaving was like breaking up with a dozen people at the same time. I’ve learned a hell of a lot, and I’ve also made some mistakes, but I’ll be better for them next time.

In the short term I’ll be starting my first gig at Mass Market. Also I’ll be cutting an updated reel – featuring the squirrel pictured above. The squirrel, fence and background is entirely computer generated (with Houdini) and wants you to not do drugs.

Update 2010-12-14
This spot has finally been released.
http://adgallery.whitehousedrugpolicy.gov/media/p/402.aspx

Apple Shake on Debian Linux 6.0 64-bit [updated]

pink — Wed, 02 Jun 2010 01:30:18 +0000

Updated for Debian 6.0 “squeeze”.

If you’re like me you think Shake was the pinnacle of image compositing packages. Everything else is just more of the same. One thing it still does better than anything is allow for back end pipelines. ALL of shakes compositing features are available from the command line. This is because in version 1, you had to build your compositing ‘trees’ by writing text files by hand (with vi of course). More or less you typed out your own .shk file.Yep, scriptwriter heaven. The actual UI didn’t appear till 1.5 or maybe 2 (my memory is hazy on this techinical bit).

So, I’m still interested in running it (on linux) to this day. However in the modern world Shake needs a little to help to run on these newer operating systems.

After a grueling few hours of crawling through the cobwebs I’ve figured it out. Assuming you’re doing most of the stuff here:

http://ubuntuforums.org/archive/index.php/t-1264840.html

You need these packages:
libx11-6_1.0.3-7_i386.deb
libxi6_1.0.1-4_i386.deb

Install the /usr/lib/lib* files in the .deb archive from to the $NR_SHAKE_LOCATION/lib/

It’s a wrap.

pink — Mon, 18 Jan 2010 08:18:41 +0000

Just finished a grueling few months on Spike Jonze’ new short film “I’m Here” premiering this Thrusday at the Sundance film festival. Have a read below. (it’s where i nabbed the really awesome pic.) Also, I’m going to finally get to snowboard that Utah snow!

http://www.slashfilm.com/2010/01/15/exclusive-first-look-spike-jonzes-im-here/

I was really proud of our team at Method Studios – well over 250 shots in about 2.5 months.